Apple Watch Ultra 4 review: I ran 22 miles to test Apple’s ultimate adventure watch

Apple designed the Ultra for summiting mountains and diving reefs. In reality? Most of us wearing one are weekend warriors chained to a 9-to-5, using an $800 rugged watch to track our steps on our commutes. With the Apple Watch Ultra 4, Apple makes having the watch on your wrist even better, whether you're working out or not.

The big headlines with the Apple Watch Ultra 4 are a new heart rate monitor, a readiness score to help you know when to push and when to rest, two days of battery life for the first time, and new Audio Intelligence features that will come later this year. Physically, it looks the same, but under the hood, this is a smarter watch.

But is it worth the upgrade if you already have the Apple Watch Ultra 3 on your wrist? I’ve been wearing the Apple Watch Ultra 4 for the past week and wore it for a 22-mile run this morning to see how the heart rate monitor compares to a physical chest strap. Read my full Apple Watch Ultra 4 review to find out more.

Apple Watch Ultra 4: Quick facts

• Improved battery life: lasts up to 50 hours per charge compared to 42 hours for the Ultra 3
• New S11 chip: Faster, more efficient processing with support for Siri AI features
• Redesigned holistic sensors: Apple says this is the most accurate heart rate sensor on a wearable; heart rate and HRV are sampled more frequently than before; HRV insights are now more readily displayed in the Health app
• New health metrics: the Ultra 4 supports a new Readiness score and Health Age metric
• Siri AI features: the Ultra 4 ships with support for Siri AI voice assistance; new "Audio Intelligence" features help you better recall life's important details

Apple Watch Ultra 4: Specs

Apple Watch Ultra 4 review: Price and availability

The Apple Watch Ultra 4 is available for preorder from September 9, 2026. Units should hit store shelves and your hands starting on September 18.

The Apple Watch Ultra 4 is $799 / AU$1,349, the same price as the Apple Watch Ultra 3 and prior models.

Apple Watch Ultra 4 review: Design and display

The Apple Watch Ultra 4 looks physically identical to the Ultra 3, boasting the same dimensions, oversized display with 3,000 nits of max brightness, an all-titanium case, and 100 meters of water resistance. It’s still available in black and natural titanium.

There are slightly more bands to choose from: the Trail Loop is now available in dark umber, sand, and Apple’s color of the year, burgundy. The Alpine Loop comes in desert, dark olive, and also burgundy. Ocean Bands are now made from translucent silicone and come in three new colors: translucent gray, translucent kelp, and translucent black.

The big difference between the Apple Watch Ultra 3 and Apple Watch Ultra 4 from a design perspective is when you flip the watch over. The heart rate sensor has been completely redesigned, but more on that below. The Apple Watch Ultra 4 also has a built-in microphone for all of the audio intelligence features coming later this year.

Apple Watch Ultra 4 review: Health and fitness tracking

The biggest difference, and the reason I think this is the best Apple Watch Ultra yet, is the new heart rate monitor loaded onto the watch. When looking at the two monitors side-by-side, the Ultra 4 and the Apple Watch Series 12 have a “32-petal design,” whereas older watches had a two-petal design. This refers to the spoke-like lines coming out of the electrode.

The green LED lights, which measure your heart rate by shining light into the skin, are bigger and more powerful. Apple says it also makes the heart rate monitor more accurate on certain skin tones, although it might still struggle if you have tattoos on your wrist.

I’ve always found the heart rate monitor on my Apple Watch Ultra 3 to be a little sketchy, and while I often put this down to how it sits on my wrist, I was keen to see how things might have changed on the Ultra 4. It’s worth noting that if, like me, you have petite wrists, you’ll need to ensure the Ultra is really tight against your wrist. I’ve found that if my watch strap isn’t tight enough, the watch just doesn’t give me a heart rate reading.

Heart rate data lies at the heart of a lot of health features on the Apple Watch, including HRV, workouts, and ovulation prediction. With the Apple Watch Ultra 4, the new heart rate monitor, along with the S-11 chip, measures your heart rate every five seconds, all day long. On the Apple Watch Ultra 3, Apple only allowed continuous heart rate monitoring during a workout, but this is a huge step in the right direction. Inside the Heart Rate app, there's a rolling two-minute chart.

On the Apple Watch Ultra 4, you’ll be able to see your Recovery HRV score, which shows signs of stress and recovery, as well as your overall HRV, which offers insights into your overall health. You can now see from your wrist if your heart rate suddenly spikes, and through the new daytime Vitals app, you're getting a much more immediate picture of what's happening, rather than having to wait till you’re asleep.

I’ve been testing the new heart rate sensor alongside a chest strap and my Oura Ring 5, and have found the Apple Watch Ultra 4 to be pretty much spot on. Here’s a graph from my recent run:

The new sensors also feed into the new daily Readiness score, which is only available on the Apple Watch Series 12 and Apple Watch Ultra 4. Readiness provides a single score out of ten with one of four different recommendations: Recover, Pace Yourself, Ready, or Go For It. Readiness updates throughout the day as new data comes in, and is based on your overnight vitals, sleep score, recent physical activity, and training load.

To get a Readiness score, you need to wear the watch for seven nights and get at least four hours of sleep per night. While I have done that, my Apple Watch got a little confused by moving time zones, so it only registered two hours of sleep as I travelled back to London from Cupertino. I’ll update this review soon when I’ve had a few days of Readiness scores. I’ll also look at how these scores compare to the likes of Body Battery on Garmin, and the Readiness score on the Oura Ring 5.

Later this year, the Health App will see big changes, including a new Health Age score that compares your physical fitness to the average for your age. There will also be a greater emphasis on things like sleep trends, heart data, and other longevity metrics. Again, I’ll be testing these as soon as they drop, but I’m excited to hear about these updates to make the Health app more useful to users.

Of course, it's worth noting that Apple isn’t reinventing the wheel — Garmin has had a Fitness Age score forever, but wearing a Garmin isn’t like having an extension of your iPhone on your wrist. While these little changes might not sound like a lot, a Readiness score can show you at a glance if you’re overtraining and putting yourself at risk of injury. Whether you’re a weekend warrior or training for your seventh marathon, knowing how well you’re coping with your training is imperative, and Apple makes this easier with the Apple Watch Ultra 4.

Another minor but exciting update I’ve found during my testing is the Steps watch face. At last, you can see your daily step count from your watch face. Sure, steps aren’t the biggest health metric to keep an eye on, but on rest days, I still like to make sure I’m closing my rings and keeping my legs moving. Unfortunately for folks with an older Apple Watch, this is a hardware thing, as Apple says it relies on the more accurate S-11 chip, so older watches won’t get the updated pedometer.

Apple Watch Ultra 4 review: Audio Intelligence

Now, to address the parts of the watch that are probably going to get headlines — the Audio Intelligence features. Here’s everything you need to know about the new Audio Intelligence features, but in a nutshell, the two features everyone is talking about are Live Rewind and Siri Recap.

Neither is available for me to test just yet; they are coming later in the year, but essentially, Live Rewind allows you to double-click on the Digital Crown of your Apple Watch Ultra 4 and get a 15-second recap of what was just said around you. The Watch will play an audible chime even if your watch is on silent and puts a microphone indicator on screen, so people around you will know you’re recording.

One example is if you’d missed the specials at a restaurant, or missed a colleague's name, you could read it from your watch. I think there’s a compelling reason here, say, if you have ADHD or struggle with auditory processing.

The trickier sell, for me and most people I’ve spoken to, is Siri Recap. This records ambient audio every 15 minutes to create an itemized CliffsNotes of your day. You can set this to record at certain times or locations, say only at work, or only after 6 pm. Apple put a lot of stress on privacy when demoing this new feature — raw audio isn’t saved, uploaded, or retrievable, and Siri Recap doesn’t identify individual speakers. It’s also designed to exclude sensitive information or hate speech.

Even with these features, there’s still the slightly blurred line around the fact that other people’s snippets of conversation could appear in my Siri Recap, without them knowing they were being recorded. This isn’t a problem Apple faces alone — the same questions can be leveled at the ambient AI, cameras, and microphones in smart glasses and other wearable devices.

Personally, I don’t think I’d ever want my watch to be silently recording in the background, but I’ll reserve judgment until I go hands-on with the features later this year. It’s also worth noting that all of these features you’ll have to opt in to — they are automatically disabled when you unbox the watch.

Apple Watch Ultra 4 review: Battery life

Even with continuous heart rate monitoring every five seconds, Apple has improved the battery life on the Apple Watch Ultra 4. You’re now getting more than two days of battery life in smartwatch mode, with 50 hours of battery life, up from 42 hours of battery life in the Ultra 3. In low power mode, you’ll get 84 hours of battery life in the Apple Watch Ultra 4, compared to 72 hours in the Ultra 3.

In workout tracking, the battery is better on the Ultra 4 too. You’ll get 25 hours of battery life for tracking workouts with full GPS and heart rate tracking. This is up from 20 hours on the Ultra 3. There’s also a Max Extended Workout mode that allows the Apple Watch Ultra 4 to track outdoor runs, walks, and hikes for up to 45 hours.

I’ve found these numbers to be pretty accurate. I’m easily getting two days of battery life on my Ultra 4. It’s 5 pm right now, and I have worn the watch all day, replying to messages from my wrist and tracking three and a half hours of workouts, and my watch has gone from 82% at 6 am to 61%.

You also get faster charging on the Apple Watch Ultra 4 — 15 minutes of charge will give you up to 18 hours of battery life.

Apple Watch Ultra 4 review: Should you buy?

This is, without question, the best Apple Watch Ultra yet. Sure, there are still things missing: I’d love a built-in LED flashlight or a second size option for smaller wrists, but the health improvements made to this watch with the continuous heart rate sensing and recovery information help you train smarter. Little things like a Readiness score and Daytime Vitals help me see, at a glance, how much my long run has impacted my body.

Would I upgrade if I had an Apple Watch Ultra 3 on my wrist? I’m not sure, as the heart rate monitoring isn’t bad on the older watch, but if you’re wearing an older Ultra, you want longer battery life, or you’re intrigued by the Audio Intelligence features, this is a watch worth buying.

If you’re on a budget, I’ve also been wearing the Apple Watch Series 12, which is similarly excellent and has all the same sensors and features as the Ultra 4. It’s also smaller, lighter, and more comfortable to wear for 24/7 sleep tracking.

With the Apple Watch Ultra 4, you’re getting Apple’s extreme durability, the best battery life on an Apple Watch, and that all-important Action Button, which really does make using your watch with sweaty fingers better, along with the native recovery metrics long requested by serious athletes. This stands out as Apple’s most competitive endurance wearable to date.