Apple Watch Ultra 3 vs Apple Watch SE 3 - Leaks, Rumors & Jaw-Dropping Upgrades Revealed

• Launch in September 2025: Both the Apple Watch Ultra 3 and Apple Watch SE 3 are expected to be unveiled at Apple’s fall event on September 9, 2025, alongside the iPhone 17. This marks the first time since 2022 that Apple refreshes its entire watch lineup (with Series 11, Ultra 3, and SE 3 all debuting together) macworld.com. Pre-orders would likely begin that week, with a release by September 19, 2025 macrumors.com macrumors.com.
• Pricing holds steady: Apple isn’t expected to raise prices. The Ultra 3 should start around $799 (with cellular included) – the same as the first two Ultras appleinsider.com. The SE 3 is likely to remain the budget option at roughly $249 for the base 40/41mm size (GPS only), keeping it affordable for families and kids macrumors.com. Apple Watch Series 11 (the new flagship model) is anticipated from about $399 (42mm) up to $429 (46mm) for GPS models, mirroring Series 10’s pricing macworld.com.
• Design & display upgrades: Don’t expect a radical redesign for Ultra 3 – it will retain the tough titanium case(49mm) with the signature orange Digital Crown and Action Button macdailynews.com. However, code in iOS 26 suggests Ultra 3 will feature a larger display (approx. 2.1 inches) with resolution 422×514 (up from 410×502 on Ultra 2) macrumors.com. That likely means narrower bezels and the largest Apple Watch screen to date, possibly a 50mm display without increasing the case size macworld.com. The SE 3, meanwhile, is rumored to adopt a modern Series 7-style design with bigger screens (~1.6″ and 1.8″) replacing the old 1.57″/1.78″ displays macrumors.com. This could correspond to new 41mm and 45mm case sizes for SE 3, bringing slimmer bezels and more screen real estate in line with recent flagship models macworld.com.
• Next-gen S11 chip in both: The Ultra 3 and SE 3 will run on Apple’s new S11 processor, but this chip is built on the same architecture as the S9/S10 chips macrumors.com. In practice, that means no major speed boost over the Series 9/10 or Ultra 2 – Apple is reportedly using the same core tech to focus on efficiency macrumors.com. Still, the S11 will be a huge jump for the SE line: the SE 3’s S11 is a big upgrade from the SE 2’s aging S8 chip, delivering much snappier performance macrumors.com. The S11 also enables modern features like on-device Siri processing and new gesture controls (e.g. the double-tap gesture) that were introduced with the S9 chip macrumors.com.
• 5G & satellite connectivity: The Apple Watch Ultra 3 is poised to be Apple’s first watch with 5G cellular support and even satellite messaging capabilities macrumors.com tomsguide.com. Apple will reportedly use a special low-power 5G RedCap modem in the Ultra 3, allowing faster data than LTE without the battery drain of full 5G macrumors.com. More dramatically, Ultra 3 is rumored to support Emergency SOS via satellite, letting users send emergency texts or calls when outside cell coverage (similar to the iPhone’s feature) macrumors.com. This could be a lifesaver for adventurers off-grid. The SE 3, being the budget model, will likely stick to LTE-only (no 5G) macworld.com macworld.com and won’t have satellite capability – those high-end connectivity features are expected to remain Ultra-exclusive.
• New health features (rumored): Both watches will run watchOS 26 and are expected to add new health capabilities. A blood pressure monitoring feature is widely rumored for 2025 Apple Watches macrumors.com. If it arrives, it won’t give exact systolic/diastolic numbers like a cuff, but will track your blood pressure trends and alert you to potential hypertension macrumors.com. This could help catch high blood pressure early, though users would still need a proper device or doctor to get precise readings macrumors.com. The Ultra 3 is most likely to get this high-blood-pressure warning feature first tomsguide.com. The SE 3 is expected to keep a pared-down health sensor set – for example, it currently lacks ECG and blood-oxygen sensors, and that may remain the case to differentiate it from pricier models macrumors.com. That said, the SE 3 could gain sleep apnea detection via watchOS updates (since it has the needed heart rate and motion sensors) macrumors.com, and Apple might finally enable the ECG app on SE this generation – some rumors speculate an ECG could be included to narrow the gap, though it’s not confirmed macworld.com.
• Battery life & charging: The Ultra 3 should maintain roughly 36-hour battery life in normal use (with up to ~60–72 hours in Low Power mode), similar to Ultra 2 appleinsider.com. There’s no indication of a huge battery capacity increase, but the efficiency gains (from the display tech and chip) might stretch battery a bit further in Ultra 3 macdailynews.com. The SE 3 will target the standard ~18-hour, all-day battery that Apple’s regular models get. One improvement on the Ultra 3 will be faster charging – it’s likely adopting the Series 10’s new charging architecture, with a larger coil and metal rear casing that enables a quicker charge to 80% in about 30 minutes macrumors.com (about 15 minutes faster than older models). The SE 3 could also see moderately faster charging or battery optimizations, though nothing specific has leaked beyond general hopes for “improved battery life, faster charging” in the new SE macrumors.com.
• Compatibility and other notes: Apple is expected to keep the same band attachment design on both models, so your existing watch bands should still work fine. (There have been whispers that Apple might eventually change the watch band mechanism after a decade appleinsider.com, but any such move isn’t confirmed for 2025.) Both new watches will come with watchOS 26 out of the box, bringing software perks like an AI-powered Workout Buddy coach for personalized fitness tips tomsguide.com macworld.com, new gesture controls (e.g. a pinch to dismiss notifications), and other “Apple Intelligence” features that leverage machine learning. Notably, while the S11 chip will support these AI-driven features, full-blown generative AI (what Apple calls Apple Intelligence) won’t run independently on the watch hardware yet – instead, some features will offload processing to a paired iPhone’s Neural Engine appleinsider.com macworld.com. In terms of device compatibility, the watches will require an iPhone (likely running iOS 26 or later) for setup; Apple Watch still doesn’t work with Android. And as always, the Ultra 3 will include premium perks like dual-frequency GPS, a depth gauge and dive computer functions, MIL-STD-810H ruggedness, and 100m water resistance for diving – whereas the SE 3 will have more basic 50m water resistance and no specialty sensors, aligning with its budget positioning.

Release Date and Pricing

Apple’s next big launch event – reportedly titled “Awe Dropping” – is set for September 9, 2025, and both the Watch Ultra 3 and Watch SE 3 are expected to be announced there macrumors.com tomsguide.com. This timing aligns with Apple’s usual iPhone/Watch fall release cycle. Notably, multiple insiders had predicted that 2024 would have no new Ultra model (Apple only introduced a new black-colored Ultra 2 last year), scheduling the Ultra 3 for 2025 instead tomsguide.com macdailynews.com. Indeed, analyst Ming-Chi Kuo and Bloomberg’s Mark Gurman both corroborated that Apple skipped an Ultra in 2024 and would launch Ultra 3 (and a new SE) in late 2025 macdailynews.com. Barring any last-minute changes, pre-orders should open shortly after the event (likely Friday, Sept. 12, 2025) and the watches would ship by the following week (around Sept. 19) macrumors.com macrumors.com.

In terms of pricing, Apple is unlikely to change its pricing structure for these models. The Apple Watch Ultra 3 is expected to start at $799 in the U.S. – the same launch price as the first-gen Ultra (2022) and Ultra 2 (2023) appleinsider.com. Apple appears to have settled on the ~$799 mark for the Ultra line, which in the U.S. includes cellular capability by default. (International prices have varied; for instance, the Ultra 2 launched at £799 in the UK, after a price cut from £849 for the original techadvisor.com.) While no specific rumors suggest a hike, some analysts warn that U.S. import tariffs could potentially force Apple to adjust prices upward if those trade policies persist appleinsider.com techadvisor.com. For now, though, $799 remains the best estimate, keeping the Ultra 3 competitive – especially as rivals like Samsung’s high-end watches are generally cheaper (a hypothetical Galaxy “Watch Ultra” might be around $649) tomsguide.com.

The Apple Watch SE 3 should remain the cheapest Apple Watch. No price increase is expected for the SE; Apple will want to keep it attractive to budget-conscious buyers and families. The current SE (2nd gen) starts at $249 for the smaller 40mm (GPS) and $279 for 44mm, with a $50-$+ charge for cellular models macrumors.com. We anticipate similar pricing for SE 3 – likely $249 for a 41mm (if the size increases) and around $279 for 45mm, with cellular versions around $50-$+ extra. Apple has been marketing the SE heavily for parents to buy for kids (especially with the Family Setup feature), so affordability is key macrumors.com. In fact, when the SE 2 launched in 2022, Apple dropped the entry price from the original SE’s $279 down to $249, and often retailers have sold it for ~$199 macworld.com. If anything, there’s speculation that Apple could even introduce a lower-cost variant or more aggressive pricing if a new plastic-bodied SE had materialized macworld.com – but since that plastic idea seems canceled, $249 is likely the floor.

Meanwhile, the Apple Watch Series 11 (the mainline successor to Series 10) will slot in between these models. Apple has kept base prices consistent for years: the Series 11 is expected to start around $399 (small size, GPS) and $429 for the larger, plus +$100 for cellular macworld.com. Series 10 in 2024 stuck to those price points, and no strong rumors suggest a change for Series 11. So for context, in late 2025 Apple’s lineup pricing should roughly be: SE 3 ~$249, Series 11 ~$399, Ultra 3 ~$799 (with some variance by size and connectivity).

Design and Display

Apple Watch Ultra 3 – familiar rugged design, bigger screen: Apple isn’t reinventing the wheel (or rather, the watch) with the Ultra 3’s appearance. All leaks point to a design very similar to the current Ultra tomsguide.com appleinsider.com. Expect the same overbuilt 49mm titanium case, flat sapphire front crystal, and distinctive features like the protruding orange-ringed Digital Crown, side button, and the programmable Action Buttonon the left side appleinsider.com macdailynews.com. The Ultra line has established a signature look aimed at adventurers, and Apple has largely kept its watch designs consistent over the years, so “it would be surprising” for them to make drastic changes now tomsguide.com. In fact, aside from the new Jet Black color option introduced for Ultra 2 last year, the overall casing and style have remained the same since the first Ultra in 2022 tomsguide.com. The Ultra 3 will almost certainly come in titanium’s natural finish and the newer black again macworld.com, offering both looks.

Where we will see a notable change is the display. Rumors consistently say the Ultra 3 will have a slightly larger screenthan its predecessors. A snippet of code found in an iOS 26 beta revealed a new resolution of 422×514 pixels designated for the Ultra 3 macrumors.com. For comparison, the Ultra 2’s display is 410×502 pixels at 49mm. This roughly 10% increase in pixel count suggests Apple has trimmed down the bezels to expand the screen size without significantly enlarging the case macdailynews.com. Supply chain reports described this as a jump from about 1.93 inches to 2.12 inches diagonal for the Ultra’s display macdailynews.com – effectively making it a ~50mm screen. If accurate, the Apple Watch Ultra 3 will boast the biggest display ever on an Apple Watch, improving visibility for maps, metrics, and outdoors use. Importantly, it’s believed the overall case dimensions will remain similar to 49mm Ultra models macworld.com macdailynews.com, just with more screen filling the front.

Apple had also been rumored to switch the Ultra to a cutting-edge microLED display (for even better brightness and efficiency), but those plans appear to be delayed. Reports now indicate that microLED is unlikely to debut in the Ultra 3 and has been pushed to 2026 or later techadvisor.com macdailynews.com. One source notes Apple originally aimed for microLED in 2025’s watch, but has postponed it to at least 2026 – possibly aligning with a future Ultra or another device like AR glasses techadvisor.com. In place of that, the Ultra 3 will likely use an improved OLED panel, adopting the “LTPO 3” technology that Apple introduced in the Series 10 macrumors.com macdailynews.com. LTPO OLED allows variable refresh rates down to very low Hz, enabling an always-on display without killing battery. The Series 10’s LTPO3 display also delivered up to 40% higher brightness at certain angles (reaching 3000 nits max) and could dim down to just 1 nit for dark conditions macrumors.com. We expect Ultra 3 to inherit these advancements – meaning an extremely bright screen for sunlight readability and a more efficient always-on mode. In short, Ultra 3’s screen will be larger, brighter, and more efficient, but still an OLED (not the long-awaited microLED just yet) macdailynews.com.

Interestingly, at least one rumor has suggested Apple might include an integrated camera on the Watch Ultra 3 – possibly built into the top of the case or the Digital Crown – to allow quick photos or FaceTime calls from your wrist tomsguide.com. Apple has patented watch camera concepts (like a camera in the band or crown), and some enthusiasts hoped the ultra-premium model could get this first. However, this idea is highly speculative. The prevailing leaks from more credible sources haven’t mentioned a camera, focusing instead on health and connectivity upgrades. So while a built-in camera on Apple Watch remains a tantalizing concept, it’s not something to bank on for the Ultra 3 unless more concrete evidence emerges tomsguide.com.

Apple Watch SE 3 – overdue redesign with bigger display: The Apple Watch SE 3 will be the first refresh of Apple’s “Special Edition” watch since 2022, and it’s expected to finally update the design. The current SE (2nd gen) inherited the older Apple Watch look – essentially the Series 4/5/6 design with relatively thick bezels, no always-on display, and 40mm/44mm case options. For 2025, rumors point to the SE 3 getting a more modern case and screen. Display analyst Ross Young leaked that the SE 3 will come in 1.6-inch and 1.8-inch screen sizes (diagonal) macrumors.com. Those dimensions aren’t a massive jump on paper from 1.57″/1.78″, but they hint that Apple is moving the SE to the 41mm and 45mm size class introduced with Series 7 macrumors.com macworld.com. In other words, SE 3 could adopt the same front design as the Series 7/8 (slimmer bezels and slightly larger display area than the SE 2). This means users get more usable screen (and a thinner, more elegant chassis) without a big size or weight penalty. It’s a significant upgrade because the display is one of the most noticeable differences when comparing an older SE to the newer series watches side by side.

Along with the size bump, there’s speculation that the SE 3 might finally get an Always-On Display (AOD) feature – something every flagship Apple Watch from Series 5 onward has had, but the SE models have lacked. Apple has kept AOD as a premium differentiator, presumably to save cost and battery on the SE. Now that AOD technology is mature (and the SE 3 will have a much more power-efficient chip), Apple could bring always-on to the budget watch. There are no solid leaks confirming AOD on SE 3 yet macrumors.com, so it’s not guaranteed. However, Macworld’s experts list it as a likely addition macworld.com, and it would make sense: an SE 3 with a modern display and AOD would look nearly as good as a high-end model when the screen is off. Even if Apple doesn’t enable always-on, the display quality itself should improve (higher resolution and brighter, thanks to the newer panel design).

In terms of materials and finishes, Apple experimented with a plastic-case SE according to rumors, but that plan seems to have been scrapped. In mid-2024, Bloomberg’s Mark Gurman reported Apple was testing a colorful plastic chassis for a future SE – akin to the old iPhone 5c’s plastic shell – to make a lighter, more kid-friendly watch in fun colors macrumors.com. Prototypes were apparently made in bright hues, potentially to appeal to children/teens and to cut costs. However, by early 2025 Gurman said this idea was in “serious jeopardy” due to design and cost issues macrumors.com. The design team was reportedly unhappy with the look, and Apple’s materials team struggled to make the plastic significantly cheaper than aluminum macrumors.com. Essentially, an SE in a plastic body wasn’t sufficiently beneficial, so Apple likely stuck with the aluminum case for the SE 3 macrumors.com. As a result, expect the SE 3 to have an aluminum build (just like the current SE and standard Series watches), offered in a few standard colors – likely Midnight (dark), Starlight (champagne/silver), and maybe Silver or a new color. (If Apple wants to entice younger buyers, we could see an additional playful color in the lineup, but no strong rumors on new colors beyond the scrapped plastic concept.) Apple will ensure the SE 3 maintains a premium feel, even if it’s the entry model, so an aluminum case with the updated design will do just that.

From a durability standpoint, the SE 3 will have the usual water resistance (50m swim-proof) and strength of an aluminum Apple Watch. It won’t match the Ultra’s extreme ruggedization (the Ultra can handle scuba diving to 40m, high-altitude temps, etc.), but it’s perfectly fine for everyday fitness and swimming. The SE 3’s design update is mostly about catching up visually and functionally to the newer generation of Apple Watches, making the affordable model look less old. And considering the SE 2 was based on a 2018/2019-era design, this 2025 SE 3 refresh is indeed overdue – as MacRumors notes, the SE “hasn’t been updated since 2022, so it is overdue for an update” macrumors.com.

Hardware and Performance (Processor, Connectivity, Compatibility)

Both the Ultra 3 and SE 3 will share the same brains: Apple’s new S11 System-in-Package (SiP). However, buyers shouldn’t expect a big performance leap over recent models, because the S11 is rumored to be essentially the same core design as the S9 and S10 chips macrumors.com. Apple introduced the S9 chip with the Series 9 and Ultra 2 in 2023, bringing a 4-core Neural Engine and doubling the transistor count for speed and efficiency. The S10 (used in Series 10, 2024) was reportedly just a minor iteration of S9, and now S11 continues that pattern macrumors.com. In fact, insider reports say S11 will offer the same performance as S9/S10 – Apple hasn’t moved to a new CPU architecture or smaller fabrication node for it macrumors.com. Instead, the benefit of S11 might be that it’s physically smaller or more power-efficient, freeing up space for other components like a bigger battery macrumors.com. So, for an Ultra 3 user coming from an Ultra 2 (S9 chip), the speed and responsiveness will likely feel about the same. And indeed, Apple’s own software support hints at this parity: features introduced with S9 (such as the on-device Siri and new double-tap gesture) will be present, but no exclusive new functions have been rumored for S11 beyond what S9/S10 already do.

For the Apple Watch SE 3, on the other hand, the S11 is a huge step up. The SE 2 uses the older S8 chip (from 2021’s Series 8), which lacks the Neural Engine and speed improvements of the S9/S10. By jumping to S11, the SE 3 effectively leapfrogs two generations. Users will notice much snappier app launches, smoother navigation, and overall faster performance. Apple accidentally leaked in code that the SE 3 would indeed get the same S11 as the flagship models macrumors.com, meaning the budget watch won’t be left with a hand-me-down processor this time. This should make the SE 3 feel as fast and fluid as a Series 11, greatly improving on the sometimes sluggish S8-based SE 2. Apple can also unlock new capabilities on the SE thanks to the chip: for example, on-device Siri requests (where Siri can process certain commands entirely offline) require the Neural Engine added in S9 macrumors.com, and the SE 3 will now have that. So things like setting timers or starting workouts via Siri will work quicker and even without Wi-Fi or iPhone connection on the SE 3 – a feature the SE 2 couldn’t do. The “Double Tap” gesture, where you tap your index finger and thumb together to control the watch one-handed, is another S9/S10 feature that the SE 3 will gain thanks to S11’s Neural Engine. Moreover, the S11 should come with more onboard storage (likely 64GB) and improved efficiency, so the SE 3 can support the latest watchOS features for years to come.

In summary, performance on Ultra 3 and SE 3 will be top-tier, but the real-world difference will be felt more by SE upgraders than by Ultra users upgrading from the last gen. Both watches will run watchOS 26 smoothly and handle advanced tasks, but they won’t outclass a Series 10 or Ultra 2 in raw speed since the silicon is comparable macrumors.com. Apple is clearly focusing the 2025 upgrades on new sensors and connectivity rather than raw horsepower.

Speaking of connectivity, there’s a big divergence between the high-end Ultra and the SE in what’s included:

• The Apple Watch Ultra 3 is expected to pack cellular connectivity by default (as the Ultra models do), now upgraded to 5G for the first time on Apple Watch macrumors.com. Currently, every Apple Watch from Series 3 through Series 9/Ultra 2 has been limited to 4G LTE for cellular models. With Ultra 3, Apple is reportedly using a MediaTek 5G RedCap modem to enable 5G on the watch macrumors.com. “RedCap” (Reduced Capability) is a flavor of 5G designed for wearables and IoT devices – it offers better speeds and coverage than LTE while consuming less power than a full 5G modem macrumors.com. This means Ultra 3 users could see faster data for things like loading map tiles, streaming music, or sending messages when away from their phone, all with improved efficiency. It’s a logical upgrade, as Apple catches the Watch’s cellular tech up to the 5G era. The Ultra 3 is also rumored to include Satellite connectivity – specifically, the ability to send SOS messages via satellite when you have no cell signal macrumors.com tomsguide.com. Apple brought Emergency SOS satellite texting to the iPhone 14 in 2022 (partnering with Globalstar satellites), and now they appear set to extend a form of this to the watch. For adventurers, this is a huge deal: in a dire emergency in the backcountry, an Ultra 3 could potentially send your coordinates and a brief message to get you help, even if your iPhone is dead or out of reach. Some reports suggest the Watch’s satellite feature might even allow limited two-way texting for non-emergencies (like an “I’m OK” message to family) macrumors.com, though emergency use is the primary focus. To support this, Apple is likely using a combination of the new modem and leveraging the iPhone’s existing satellite service infrastructure. There may be technical limitations (for example, you’d probably need to hold the watch up to the sky and have a clear view for it to connect, similar to the phone), but just having satellite capability on a wrist device would be an impressive first in the smartwatch world. Aside from these headline features, Ultra 3 will of course support the usual Wi-Fi (likely dual-band), Bluetooth (for connecting to accessories), NFC (Apple Pay), and Ultra Wideband. The Ultra 2 and Series 9 introduced the new U2 ultrawideband chip, which improves Precision Finding for locating your iPhone or sharing AirTags’ location. The Ultra 3 should include the same UWB tech, enabling more precise device-to-device interactions within Apple’s ecosystem. And GPS is a given – the Ultra line has the best-in-class dual-frequency GPS (L1+L5) for greater accuracy in challenging environments, which the Ultra 3 will continue to offer for hikers and runners.
• The Apple Watch SE 3, on the other hand, will likely come in both GPS-only and GPS + Cellular variants, as previous SE models have. 5G is not expected on the SE 3 – it will stick with an LTE modem for the cellular versions macworld.com. This is partly to save cost and battery life, and partly to keep the premium features to the higher-end watches. 5G on a watch is cutting-edge, so Apple will limit that to the flagship series (Series 11 and Ultra 3). The SE 3’s connectivity suite will otherwise be standard: Bluetooth for headphones and accessories, Wi-Fi (which might be 2.4GHz-only or also 5GHz; current SE supports 2.4GHz), NFC for Apple Pay, and likely the updated Ultra Wideband (U2) chip as well. It would make sense for Apple to include UWB even on the SE 3, since UWB is becoming central to Apple’s ecosystem (for things like unlocking your car or Precision Finding). The SE 2 unfortunately did not get the U1 chip when it launched (the flagship Series 6 had it, but SE 2 didn’t), so it’s possible Apple will omit UWB again on SE 3 to cut costs. We haven’t heard a specific rumor either way on UWB in SE 3. However, given that by 2025 UWB will be in iPhones, AirPods, etc., it’d be a welcome surprise if SE 3 gets it, enabling features like using your watch as a digital car key (which currently requires a U1/U2 chip). Regardless, the SE 3 will not have any of the special connectivity tricks like satellite messaging – those remain exclusive to the Ultra. And naturally, if you opt for the GPS-only SE 3 model, you’ll need your iPhone nearby to make calls or send texts (the cellular SE 3 will let you do those independently on LTE).

One more aspect of “compatibility” to cover: band compatibility. Apple has used the same band attachment mechanism on the Apple Watch since 2015, meaning bands are interchangeable across most models (within size classes). There was concern that Apple might change the band design for the 2025 watches – possibly to accommodate larger screens or new sensors – which would render older bands unusable appleinsider.com. However, so far rumors indicate that Apple Watch Ultra 3 and SE 3 will continue to support existing watch bands (49mm Ultra uses the 44/45mm+ bands, and the new SE 3 in 41/45mm would use the 41/45mm bands). Apple knows many customers have invested in multiple bands, and maintaining that ecosystem is part of the Apple Watch’s appeal. It appears any band redesign, if in the works, isn’t happening this year appleinsider.com. So, you’ll be able to dress up your Ultra 3 or SE 3 with your collection of straps right away. The charging puck and basic sensors also remain in the same spot, so existing chargers and accessories should work as well (with the caveat that Ultra 3 may charge faster if used with a higher-power USB-C adapter due to its new coil).

Health, Sensors and Features

Health and wellness have become the centerpiece of Apple Watch improvements, and 2025’s models continue that trend. Apple Watch Ultra 3 is expected to introduce some new health monitoring capabilities (with some likely shared by Series 11), while the SE 3 will focus on core health features without the more advanced sensors.

The most significant rumored addition is blood pressure monitoring. Apple has been working for years on bringing blood pressure sensing to the Watch, and multiple sources claim 2025 is the year it might finally debut macrumors.com macdailynews.com. Don’t imagine you’ll be strapping a mini blood pressure cuff to your wrist, though – the implementation is reportedly non-invasive and trend-based. Leaks say the watch will not display exact systolic/diastolic readings like a traditional monitor macrumors.com. Instead, it would detect anomalies and notify the user if it sees signs of hypertension (high blood pressure) over time macrumors.com. The idea is early detection: many people have elevated BP and don’t know it, so the watch could prompt you to get checked with a doctor if it notices a trend. This feature might use a combination of the optical heart rate sensor and other sensors (perhaps analyzing pulse wave velocity). It’s expected to be a premium feature on the 2025 watches – most likely included on Series 11 and Ultra 3, but probably not on the SE 3 if Apple keeps it high-end only macrumors.com. There’s a chance the SE 3 misses out since historically Apple doesn’t give the SE new cutting-edge health sensors (the SE line famously lacks the ECG and SpO₂ sensors found in the flagship models). So, Ultra 3 will almost certainly have blood-pressure detection if it’s ready tomsguide.com, whereas SE 3 likely will not. Apple could surprise us, but given the SE 3 is about keeping costs down, any expensive new sensor or feature like that would be omitted.

What about the existing advanced sensors like ECG (electrocardiogram), Blood Oxygen (SpO₂), and Body Temperature? The Ultra 3 will include all the current top-end sensors. That means it will have the ECG capability(using electrodes in the Digital Crown and back crystal) to take medical-grade single-lead electrocardiograms and detect AFib – just as the Ultra 2 and recent Series watches do. It will also have the blood oxygen sensor (red/infrared LEDs on the back) to measure oxygen saturation, and the temperature sensor that Apple introduced with Series 8 for cycle tracking and sleep analysis. In fact, Ultra 3 owners can expect the full suite: heart rate, ECG, blood O₂, temperature, GPS, compass, always-on altimeter, depth gauge, etc. One note: Apple had a legal kerfuffle in 2023/2024 over the blood oxygen feature (a patent dispute with Masimo led to a temporary import ban threat), but Apple found a workaround and re-enabled Blood Oxygen on Apple Watches by late 2025 appleinsider.com appleinsider.com. So the Ultra 3 will ship with blood oxygen monitoring active and ready appleinsider.com, presumably with whatever behind-the-scenes tweak Apple made to satisfy the legal issues.

For the Apple Watch SE 3, historically Apple has not included the ECG or blood oxygen sensors in the SE models to differentiate them from the flagship watches. The SE has always focused on core health: optical heart rate sensor, calorie and activity tracking, sleep tracking, fall detection, etc., but no ECG app and no SpO₂ readings. We anticipate SE 3 will continue this pattern, at least regarding ECG and SpO₂ macrumors.com. This means the SE 3 likely won’t have the ECG electrodes or the dedicated blood oxygen hardware. That said, the SE 3 will carry over all the essential sensors it already has, and possibly get upgrades to some of them. For example, the optical heart rate sensor on SE 3 could be updated to the newer 3rd-generation version that first appeared in Series 7 macrumors.com. The current SE 2 is using an older 2nd-gen heart sensor (from Series 4/5 era). A 3rd-gen sensor would improve accuracy for heart rate readings during workouts and at rest. It could also enable features like Sleep Apnea detection. Apple is reportedly working on using Watch data (heart rate fluctuations, blood oxygen dips during sleep, etc.) to detect signs of sleep apnea. In watchOS 10, they quietly added a metric for “Respiratory rate variation” during sleep for Series 8/9/Ultra users, which is a hint at apnea detection. MacRumors notes that sleep apnea detection might be expanded to SE 3 since it has the needed sensors (heart rate and accelerometer, possibly with a better sensor, it can do it) macrumors.com. This would be a software feature, likely enabled across all watches with sufficient sensors via watchOS. Indeed, currently Apple limits some advanced health algorithms (like irregular heart rhythm notifications, cardio fitness estimates, and the new sleep respiratory metrics) to the watches with newer sensors or chips. With SE 3 moving to S11 and a newer sensor, it will be capable enough to get these features.

As for body temperature sensing, the SE 3 probably will not include that sensor, as it’s relatively costly and was left out of SE 2. So cycle tracking with temperature and certain advanced sleep analysis will remain exclusive to Series/Ultra lines.

It’s also worth mentioning one far-out “holy grail” sensor Apple is exploring: non-invasive blood glucose monitoring(for diabetes management). This has been in R&D for years. Rumors in early 2023 stirred excitement that Apple had made progress on a no-prick glucose sensor for Apple Watch. However, the consensus now is that this technology is still years away from commercialization macworld.com. Don’t expect anything like that on Ultra 3 or SE 3. At best, Apple might eventually introduce the ability to pair a third-party continuous glucose monitor (CGM) or show glucose data from a sensor, but an Apple-built glucose sensor is not coming in 2025.

Beyond pure health sensors, there are other user-facing features to consider:

• Safety & tracking: Both watches will support features like Fall Detection, Crash Detection (using accelerometer and gyroscope to sense accidents), Emergency SOS calling, and international emergency calling (on cellular models). The Ultra, being more adventure-focused, also has a loud siren feature and dual-frequency GPS for more accurate location tracking in challenging terrain – these will continue in Ultra 3. The SE 3 will have standard GPS (single frequency) which is sufficient for most users, just slightly less accurate in canyons or cities.
• Environment sensors: The Ultra 3 has an advanced altimeter and depth gauge (for divers, it measures depth and water temperature). It’s safe to assume Ultra 3 keeps these, and possibly even enhances water resistance standards if any changes (currently WR100 and EN13319 for diving to 40m). The SE 3 will have the basic always-on altimeter and compass, but not the depth or high-depth rating (SE is typically WR50 for swimming, not diving).
• New fitness/coaching features: A big theme for watchOS 26 and Apple’s 2025 lineup is integrating more AI-powered coaching. Apple has been developing a coaching service codenamed Quartz, and at WWDC 2025 they likely highlighted a “Workout Buddy” feature in watchOS 26 tomsguide.com. This uses machine learning to analyze your fitness trends and give you personalized training plans and motivational prompts. According to Tom’s Guide and Macworld, the Workout Buddy will provide things like tailored workout suggestions, post-workout analysis, and even pep-talk style messages based on your performance tomsguide.com macworld.com. It might say, for example, “You crushed your run today – 5% faster than last week’s pace!” or encourage you if you’re close to a goal. This kind of feature will be available on all Apple Watch models that run watchOS 26, but it’s being marketed as part of the new watches’ experience (taking advantage of those Neural Engines). So both Ultra 3 and SE 3 will support these AI fitness coaching features, though note that the heavy lifting for AI (like generating personalized plans) may be done on the iPhone and delivered to the Watch macworld.com. Another new tidbit in watchOS 26 is improved voice transcription on the watch (leveraging “Apple Intelligence” on iPhone) so you can see live transcripts of calls or messages on your watch macworld.com – again something all watches paired with an iPhone can do, but highlighted for new models.
• Gesture and UI enhancements: With the S11 chip, both watches will support the nifty Double Tap gesture that Apple debuted with Series 9. By tapping your thumb and index finger together twice, you can answer calls, play/pause music, or scroll through widgets, all without touching the screen – useful when your other hand is occupied. This works through the Neural Engine analyzing subtle wrist movements and blood flow changes. It was a headline feature for Series 9/Ultra 2 and will be a standard feature on Series 11/Ultra 3 and now SE 3 thanks to S11. Additionally, watchOS 26 is expected to refine the Smart Stack widgets introduced in watchOS 10, possibly making them context-aware (e.g., showing certain widgets at certain times). There’s mention of new gestures to dismiss notifications more easily macworld.com and other minor UI improvements that the new watches will leverage.

In short, Ultra 3 is getting the cutting-edge health and connectivity features – blood pressure alerts, satellite SOS, 5G – on top of all the sensors Apple already offers, making it a powerhouse for health and safety. The SE 3 is catching up on performance and design, and will cover all the core fitness/health basics (heart rate, step count, sleep tracking, GPS, fall detection, etc.) with improved accuracy and speed, but will likely omit the more advanced sensors like ECG and SpO₂ to remain an “essentials” device. Both will benefit from new software and AI features in watchOS 26, bringing smarter health insights and convenience features to users.

Comparison to Previous Models (Ultra 2 vs Ultra 3, SE 2 vs SE 3)

To appreciate the upgrades, let’s compare how the Ultra 3 and SE 3 stack up against their immediate predecessors:

• Ultra 3 vs Ultra 2: The Apple Watch Ultra 2 (released in 2023) introduced the S9 chip and boosted the max brightness to 3000 nits, but was otherwise very similar to the original Ultra. Apple even skipped a new Ultra in 2024 (only adding a black color), so the Ultra 3 comes after a two-year gap in new hardware. As a result, Ultra 3 brings several significant enhancements. Firstly, the display: Ultra 3’s screen is about 0.2″ larger with noticeably thinner bezels macrumors.com, giving a more immersive display than Ultra 2’s 1.9″ screen. The Ultra 3’s adoption of the Series 10 display tech (LTPO3) means better viewing angles and potentially an always-on second hand that’s visible at 1 nit brightness macrumors.com (Series 10 allowed the second hand to sweep even when wrist-down, which Ultra 2 couldn’t do). Secondly, the connectivity leap: Ultra 2 is LTE-only and has no satellite function, whereas Ultra 3 is adding 5G and emergency satellite messaging macrumors.com tomsguide.com – a major upgrade for those who go off-grid or just want faster data. In health features, Ultra 2 has ECG and blood oxygen, but Ultra 3 is expected to add Blood Pressure monitoring alerts for the first time macrumors.com. If that materializes, that’s a headline new capability that Ultra 2 lacks. Other improvements: Ultra 3 will charge faster (thanks to the new charging coil design borrowed from Series 10) macrumors.com, whereas Ultra 2 takes about 45 minutes to hit 80%, Ultra 3 should do it in ~30 minutes. The processor S11 in Ultra 3 is basically on par with Ultra 2’s S9 for speed, so everyday performance might feel the same; however, Ultra 3’s S11 may run a bit cooler or use slightly less power due to optimizations macrumors.com. Battery life remains roughly the same 36 hours, as Apple likely didn’t change the battery drastically – though any efficiency gains could give Ultra 3 a small edge (maybe an hour or two more in real-world use, according to some speculation macdailynews.com). Design-wise, they look nearly identical and both are heavy-duty titanium watches. So, how significant is the Ultra 3 upgrade? It appears incremental but meaningful. One tech outlet described the Ultra 3 as an “iterative update, focusing on health, connectivity, and display enhancements rather than a bold redesign” macdailynews.com. For an Ultra 2 owner, the new model will feel familiar – no radical changes – but the added features (satellite SOS, BP monitoring, etc.) could still be very compelling if you value those. For someone coming from an older or standard Apple Watch, the Ultra 3 will be a huge leap in capability. And for the adventurers or tech enthusiasts, Ultra 3 packs the absolute latest Apple has to offer in a watch in 2025.
• SE 3 vs SE 2: The jump from Apple Watch SE (2022) to SE 3 (2025) is quite substantial, more so than the Ultra’s jump, because the SE line was two generations behind in several aspects. Design/display is the most obvious change: SE 2 has the old 40/44mm case with no always-on display and thicker bezels, whereas SE 3 moves to a larger, refined 41/45mm design (likely with the option of an always-on display) macrumors.com macworld.com. Visually, the SE 3 will look much more modern and give users more screen (and more watch face complications) than SE 2. In performance, SE 2’s S8 chip is being leapfrogged by the S11 in SE 3 – Apple claims about a 20% jump from S8 to S9, and S11 is similar to S9, so expect roughly 20%+ faster performance and the enablement of features like on-device Siri that SE 2 doesn’t support macrumors.com. This means the SE 3 will feel much more responsive and future-proof than the SE 2, which was essentially using a 2021 processor. Health and sensors: SE 2 lacks ECG and blood oxygen, and unfortunately the SE 3 will likely also lack those to remain a budget model macrumors.com. However, SE 3 should get the upgraded heart sensor (for better heart-rate accuracy) and will benefit from new health algorithms like sleep apnea detection, which SE 2 might never get macrumors.com. Battery life on SE 3 should be similar to SE 2’s all-day life (18 hours), though the more efficient chip might help it last a bit longer or at least not drain faster even if an always-on display is added. One small win: if SE 3 includes the new charging coil design or simply improved power management, it might charge a bit faster or run cooler than SE 2 (which used the older charging system). Another difference is Ultra Wideband – SE 2 had no UWB, whereas SE 3 might include the U2 chip (to be confirmed), which would enable Precision Find for iPhones and such. On connectivity, SE 3 will remain LTE for cellular, same as SE 2; no 5G, as expected. Summing it up, the SE 3 is a major upgrade over SE 2 in speed and display. It closes much of the feature gap with the flagship models (especially if it gets always-on display). Current SE 2 users will notice a big improvement in how the watch looks and performs. Apple likely wants to extend the appeal of the SE, and by giving it the Series 7-era design and a current chip, the SE 3 will feel far more “premium” than the last gen, despite its role as the entry model. And importantly, Apple is doing this while keeping the price down macrumors.com, which could make SE 3 one of the best value smartwatches on the market for mainstream users.

Finally, a word on the Apple Watch Series 10 and Series 11 for context: The Series 10 (launched in 2024, marking the 10th anniversary of Apple Watch) introduced the new 42mm/46mm sizing with an edge-to-edge LTPO3 display and a slightly thinner chassis, plus that fast-charge coil and S10 chip macrumors.com macrumors.com. The Series 11 (expected alongside Ultra 3 and SE 3 in 2025) is believed to be an iterative update, largely keeping Series 10’s design and adding S11 and new features like blood pressure detection and 5G macworld.com macworld.com. So, the Series 11 will share many of the upgrades of Ultra 3 (aside from the extreme stuff) and sits in between Ultra 3 and SE 3. If you’re comparing across the lineup: Ultra 3 is for those who want the biggest, toughest watch with every feature Apple offers; the Series 11will be a polished all-rounder with almost all the latest tech except the Ultra-exclusive bits; and the SE 3 will cover the fundamentals with a fresh design and strong performance, at a wallet-friendly price. All three are shaping up to make the Apple Watch family in 2025 the most comprehensive ever, catering to budget buyers, average consumers, and hardcore enthusiasts alike.

In conclusion, the Apple Watch Ultra 3 and Apple Watch SE 3 represent two very different ends of Apple’s 2025 smartwatch spectrum – one a no-compromise flagship for adventurers, and the other a value-packed entry model – yet both are receiving meaningful updates. The Ultra 3 is doubling down on Apple’s lead in wearable tech by adding things like satellite connectivity and advanced health tracking that few (if any) competitors offer tomsguide.com. The SE 3 is bringing a long-awaited refresh to Apple’s budget line, ensuring that even cost-conscious users get a modern, fast, and feature-rich experience. Whether you’re after the “best of the best” watch or just “the best for the money,” Apple’s upcoming Watch lineup has something in store. As we await the official reveal, the credible leaks and rumors paint an exciting picture: bigger and better displays, faster chips, new health superpowers, and the integration of more AI smarts. If these rumors hold true, Apple Watch Ultra 3 and SE 3 will make 2025 an “awe-dropping” year for Apple Watch fans macrumors.com, with upgrades that analysts say could be game-changing in their own ways – from life-saving emergency features to simply making the Apple Watch experience more accessible and enjoyable for all macdailynews.com macdailynews.com.

Sources:

1. Juli Clover, MacRumors – “Apple Watch Ultra 3 Coming Soon: What to Expect” (Aug 28, 2025) macrumors.com macrumors.com
2. Juli Clover, MacRumors – “Apple Watch SE 3: What to Expect From Apple’s Upcoming Budget Smartwatch” (Aug 29, 2025) macrumors.com macrumors.com
3. Karen Haslam & Jason Cross, Macworld – “New Apple Watch 2025: Series 11, Ultra 3, and SE 3” (Sep 2, 2025) macworld.com macworld.com
4. Dan Bracaglia, Tom’s Guide – “Apple Watch Ultra 3 — all the leaks and rumors so far” (Sept 4, 2025) tomsguide.com tomsguide.com
5. AppleInsider – “Apple Watch Ultra 3: Rumors, price, release date” (2025) appleinsider.com appleinsider.com
6. Chris Martin, Tech Advisor – “Apple Watch Ultra 3: Release Date, Price & Specs Rumours” (Sep 2, 2025) techadvisor.com techadvisor.com
7. MacDailyNews – “What the rumor mill says about Apple Watch Ultra 3” (June 23, 2025) macdailynews.com macdailynews.com