Apple Watch Ultra 4 Review

Design and screen

• Same design as Apple Watch Ultra 3
• Slightly heavier than Ultra 3
• Introduces new sensor system 

The Apple Watch Ultra 4 is basically identical to the Apple Watch Ultra 3. It has the same 49mm-sized grade 5 titanium case, the same overall case thickness, the same physical buttons, and the same strap style options. There’s technically a touch more weight to handle, but it’s a negligible amount you just don’t notice day-to-day.

Many will be happy that Apple hasn’t made drastic changes. I was sort of hoping it might follow the trend of adding in a proper flashlight, but that hasn’t happened.

It remains a smartwatch that, while blockier than most other smartwatches, does have the typical Apple build quality and comes with a strap that’s easy to remove and replace. I always find it startling how quickly I adjust to having that large case sitting on my skinny wrists.

Something you can’t fault is Apple’s ability to pick and match up case colours with strap options. I had the black Ultra 4 and opted to combine it with the burgundy trail loop, and it’s a stylish combination. You can still use Ultra 3 straps with it if you’re not willing to give up on some favourite bands you’ve already picked up.

Flip the watch over, and you’ll find the biggest design difference with the Ultra 3. Apple has introduced its new health sensing system, which takes care of tracking various biometric data, including heart rate and temperature.

Apple says it’s increased the surface area for the electrodes that conduct readings, added larger LEDs and can now monitor metrics like heart rate more frequently than previous watches. The new sensor didn’t seem to alter how the watch sat on my wrist and works with the same-style charging puck as previous Ultras.

Performance and software

• Runs on watchOS 27
• New S11 chip unlocks new audio features
• Siri Recap and Live Rewind features not yet live

The Ultra 4 comes packed with Apple’s new S11 chip, which it’s dubbed its most powerful wearable chip. That’s powering watchOS 27, where key software highlights include a version of Siri that goes beyond answering simple queries and functions a bit more like ChatGPT. There’s now a new grid layout to get to the apps you use most in a quicker fashion, with more features on the health and fitness front.

The Siri improvements are intriguing ones. If you open up the Siri app on your iPhone, you can now see previous conversations you’ve had with the assistant. I was also able to have a conversation about my calendar and delve deeper into a hotel I booked and whether it offered late check-outs. The responses, while not instant, were dealt with pretty swiftly and, crucially, offered useful responses.

The new dynamic grid wasn’t a feature I found hugely life-changing, though I did appreciate using the new tap gesture to navigate Apple’s smart stack screen when I didn’t have a hand free to do it from the watch crown.

Apple is making a big play on voice, with a range of new features it’s tagged as Audio Intelligence. Some features are live, some aren’t. They use the now more powerful S11 chip and the Ultra’s microphone to deliver more sophisticated audio-based features. I was able to use the new sound recognition mode, which was swiftly able to recognise my daughter’s crying. The now quicker reacting Shazam integration identified a song playing on the radio in the gym without me prompting the Watch to do anything. 

What isn’t available is the new Live Rewind and Siri Recap modes, which are coming later in the year. Live Rewind lets you record the last 15 seconds of a conversation while Siri Recap can summarise conversations like meetings you’ve had in the day.

Apple does emphasise the private nature of using these audio-based features, including that it doesn’t store recordings or give access to recordings. That said, these are features that have understandably raised eyebrows, and no doubt will continue to do so when users can start putting them to use.

Beyond those new features, the Ultra 4 still performs great at being a smartwatch that handles smartphone notifications, music features, making payments and giving you access to great apps and watch faces in a very polished way. And, yes, it continues to be an iOS-only wearable.

Tracking and features

• New health sensing system brings more accurate heart rate tracking
• New daytime and nighttime vitals views
• Redesigned Health app not yet live

The headline feature on the Watch Ultra 4 is Apple’s new Health Sensing System, which also appears on the Watch Series 12.  When combined with Apple’s new chip, it can mainly sample heart rate data at a higher frequency than previous Watches. This should lead to more accurate heart rate tracking and also unlock new health and fitness-related features. 

That includes new Readiness scores to assess whether you’re in good shape to take on your day. There’s now more insight into your recovery from a tough day or workout, and a closer look at how vitals data can change from day to night. Some of these features, like readiness scores and HRV recovery, have been available on rival smartwatches for some time.

Let’s deal with accuracy first. I’ve had a mixed experience with the heart rate tracking on previous versions of the Ultra. More so during exercise.

For resting heart rate readings and tracking heart rate during sleep, it’s generally been fine. I’ve used the Ultra 4 for a range of exercises and also raced with it up against a chest strap monitor. While I found the average readings similar, I found it slightly underreported maximum heart rate against a chest strap. The heart rate graphs in general looked similar, and I was pretty satisfied with the performance. It’s not spotless, but it’s been solid on the whole.

Dealing with the Readiness scores next and these require seven nights’ worth of sleep alongside capturing other metrics like sleep scores, heart rate variability and vitals data including respiratory rate and wrist temperature. I’ve been comparing scores to Garmin’s similar training readiness scores and scores generated by third-party app Bevel. Looking at data after a race, I could see those scores were telling me similar things. Basically, it takes some time to recover. 

Apple says scores dynamically adjust during the day based on your data. So I could see that on one day my score was a 7 and adjusted to a 6 based on the exertions or running around completing errands and squeezing in a workout during my day.

They’re nicely presented on the watch, but when it comes to reviewing it off the small screen, things get a little more archaic. This is why it’s good news Apple is deciding to overhaul its Health app, even if that overhauled app isn’t quite ready just yet.

Apple is going big on HRV (heart rate variability), which again, isn’t a new metric to smartwatches. It’s a heart rate-based metric closely tied to recovery. I’ve been comparing similar readings to a Garmin watch, and the average measurements have been similar on most days. Like Garmin, the information in isolation doesn’t feel hugely insightful. That’s likely why it has been pulled into the new Readiness and Vitals data to put it to better use.

Moving onto Vitals next, Apple is essentially letting you see a daytime and nighttime view of how data like heart rate, HRV and temperature might change. It’s easy to toggle between the two views, though I wouldn’t say it’s as glanceable as the new Readiness scores.

Another aspect of tracking that Apple promises improvements is with tracking your step counts. I’ve been wearing the Ultra 4 with a range of different smartwatches and smart rings. I found daily step totals typically to be a few hundred steps within daily totals of other trackers. The GPS performance in that half marathon test was strong too, even on a twisty and turning course, where I expected to have issues. 

• Over 2 days battery life
• Up to 84 hours in low power tracking mode
• Fully charges in just over an hour

The wait for an Apple Watch that can last a week does unfortunately go on. Instead, Apple has managed to increase the Ultra’s stamina so that it can last over 2 days. That’s up from 42 hours to 50 hours on the Ultra 2.

That improvement is my experience of living with the Ultra 4. I averaged getting two days before I was prompted to turn on the low power mode, and never quite made it to three days. That time included using the GPS, receiving notifications, using music features and interactions with Siri throughout the day and tracking sleep.

Apple has also boosted the battery life when tracking exercise. So now the Ultra 4 can last up to 18 hours in its most accurate GPS tracking mode, which is up from 14 hours. Stick it into Apple’s extended workout mode, and you can expect anywhere from 25 to 45 hours. When I wore the Ultra 4 for a half marathon race, which lasted just over an hour and a half, the battery dropped by 7%. 

To compensate for the fact that the battery is shorter than most of the competition, Apple includes a pretty speedy fast charging mode. You can get up to 80% battery from a 45-minute charge or enough battery to cover a night’s worth of sleep tracking from a 5-minute charge.

So, yes the Apple Watch Ultra 4 has better battery life than the Ultra 3. Is it still enough? No. Will an Apple Watch Ultra 4 that can last over 2 days keep some fans happy? I imagine it will, especially with how quickly it can charge up.

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Should you buy it?