Apple Watch Ultra 4 vs Watch Ultra 3: Is it worth spending another $799?

A quick look at the specs shows that the Apple Watch Ultra 4 is very similar to last year’s Ultra 3. The same 49mm titanium case houses the same large display with 3,000 nits of brightness, a side-mounted Action button, satellite connectivity, water resistance to 100 meters and support for recreational diving up to 40 meters. Apple didn’t even change the two body colors.

But that’s just the hardware side of the story. Look under the familiar body and everything starts to look much newer. Ultra 4 introduces a completely new health measurement system, higher frequency heart rate and HRV measurements and more. It also starts at the same $799 price that the Ultra 3 launched at, so for those buying their first Apple Watch Ultra, the decision may be obvious. Although this does not apply to existing Watch Ultra 3 owners.

Characteristics of Apple Watch Ultra 4 and Watch Ultra 3

Apple’s technical specifications confirm that physical aspects such as dimensions, display resolution, peak brightness, water resistance, storage capacity and basic connectivity remain largely unchanged.

Design and Display: This is essentially a draw.

If you were hoping Apple had shrunk the Ultra size again, you’ll be disappointed. Both generations are 49mm high, 44mm wide and 12mm thick. The Ultra 4 actually gained a bit of weight, coming in at 63 grams in natural titanium compared to the Ultra 3’s 61.6 grams. While Apple may say the Ultra is thinner, the 1.4 gram difference won’t make a difference in real-world use.

The display is also unchanged: both models use a wide-angle LTPO3 422 x 514 OLED panel with a display area of ​​1245 mm², Always-On capability at 1 Hz and brightness from 1 to 3000 nits. In our review of the Apple Watch Ultra 3, we praised its thinner design and wider viewing angles as one of the biggest improvements Apple has made to the Ultra line. Finally, Apple’s huge adventure watch makes everyday life a lot easier.

Health Tracking: Ultra 4 wins by a landslide

This is where the generation gap finally opens up. Ultra 4 features Apple’s new health monitoring system, built around upgraded optical and electrical sensors and the S11 chip. Larger, more efficient green LEDs allow the watch to measure your heart rate every five seconds throughout the day, and Apple says it can now measure HRV 24 times more often.

The additional data provides several new features. The biggest one is the new readiness feature. Essentially, it combines recent activity, training load, sleep score, vital signs, and recovery information into a score from 0 to 10. Instead of just passing on a number, Apple categorizes your condition as Recovery, Speed, Readiness, or Action. The score may also change throughout the day as new training and health data becomes available.

Apple is also separating HRV Recovery from broader HRV trends and adding HRV to Vital Signs. Daytime Vitals can detect changes before bed, making Ultra 4 significantly more useful for athletes trying to assess recovery and training readiness. This addresses one of the more prominent holes in Apple’s previous fitness offering, finally offering a single daily recovery metric that competitors like Garmin, Oura and Whoop have emphasized.

Fitness and GPS: Mostly familiar, with more stamina.

Both watches remain extremely capable sports devices. You get precision dual-frequency GPS, custom workouts, heart rate zones, race route, pacemaker, training load, auto track detection, bike power meter support, offline hike maps, swim metrics, and recreational scuba diving.

Apple once again claims that Ultra 4 delivers the most accurate built-in GPS in a sports watch, based on testing with leading dual-frequency sports watches in August 2026. Interestingly, Apple made a similar accuracy claim with the Ultra 3 last year, and both specs still list accurate dual-frequency GPS. Therefore, I wouldn’t call it a new major GPS hardware system without more testing.

Although Apple says indoor step and distance tracking has become more explicit thanks to redesigned pedometer algorithms on the S11 chip, which improve all-day step counting and distance estimation on the treadmill. These changes won’t impact the average user, but athletes who are particularly concerned about recovery data will get a much bigger upgrade with readiness and more frequent heart rate measurement.

S11 and Software: Don’t Upgrade Just for Siri AI

The S11 chip sounds like an easy reason to choose the Ultra 4. Except for one minor detail to keep in mind. Siri AI is not an exclusive feature of the Watch Ultra 4. Apple says watchOS 27 supports Apple Watch Ultra 2 and later, and Siri AI can run on those supported watches when paired with a compatible Apple Intelligence-enabled iPhone.

This means your Ultra 3 will still get Apple’s much more conversational assistant, personalized context recognition, a dedicated Siri app, a dynamic app grid, a smarter Smart Stack, and many other watchOS 27 improvements. What’s really new is the hardware-exclusive Audio Intelligence feature. The S11 chip contains a Secure Enclave designed for independent audio processing, allowing the Ultra 4 to support four new features: audio recognition, faster automatic Shazam, live rewind and Siri Recap.

Live Rewind can restore the previous 15 seconds of a conversation as text when you double-tap the Digital Crown. Siri Recap goes even further by creating a general summary of conversations that you can return to later. Apple says neither feature retains raw audio, and both will be available in beta later in 2026.

Battery Life: This is an update that people might notice right away.

Battery life was already one of the Ultra 3’s biggest strengths, with Apple rated it at up to 42 hours in normal use and 72 hours in Low Power mode. During one of our tests, it had 31% charge remaining even after nearly 60 hours of use, demonstrating just how long its endurance can be with mixed use.

The latest generation extends normal use to 50 hours and low power mode to 84 hours. Regular outdoor training with full GPS and heart rate measurement is extended from 2 p.m. to 6 p.m. Apple’s new Enhanced Workout Mode allows you to work out up to 25 hours while retaining all GPS and heart rate data.

There’s also a Max Extended Workout mode for up to 45 hours of outdoor running, walking or hiking, with GPS readings taken every second. Apple specifically claims that this is enough for many 100-mile races. Both watches reach 80% in about 45 minutes, but 15 minutes on the charger now gives the Ultra 4 up to 18 hours of normal use, compared to 12 hours on the Ultra 3. Five minutes gives up to 10 hours of sleep tracking instead of eight.

Apple Watch Ultra 4 vs Ultra 3: what to buy?

For a new Apple Watch Ultra buyer, get the Ultra 4 if you’ve been waiting to buy it. Apple has kept the $799 starting price while improving the areas that actually make sense for this product. Readiness and higher HRV rates are pretty big updates in the health tracking department. The health measurement system collects significantly more physiological data, and battery life is increasingly moving into the realm of sports watches.

This is a simple recommendation when the alternative costs the same (without discount). So if you’re already using the Watch 3 Ultra, it’s best to stick with it. The display and appearance are almost identical. You already have 5G, satellite connectivity, precision dual-frequency GPS, excellent battery life, and almost the entire Ultra fitness suite. Most importantly, watchOS 27 means you won’t be locked out of Siri AI or Apple’s larger software update in just a year.