// WIRED US/UK — HARDWARE & GADGET
Apple Watch Ultra 4 Review: The Series 12 Is Closing the Gap
Not much has changed about the Apple Watch Ultra since its debut in 2022. The company’s heavy-duty smartwatch is still massive, titanium-clad, and equipped with enough emergency features to make one feel slightly more prepared for an apocalypse than the average Joe. Each generation has brought incremental improvements, but the Ultra has largely stuck to the formula, and this year’s release isn’t any different.
After testing both the Ultra 4 and the new Series 12, I noticed how little separates the two Apple Watches. The gap between them seems to shrink a little further every year, leaving fewer reasons to pay $799 for the beefier version. The Series 12 now shares many of the Ultra 4’s health and safety capabilities, and the Ultra’s biggest differentiators—its multiday battery, dedicated Action button, and satellite messaging—are more tailored to people who actually spend time off the grid.
This makes the Ultra 4 a more specialized smartwatch than ever, but also a tougher sell. Its benefits are clear for trail runners, divers, or anyone who regularly ventures outside cellular coverage. However, if your main goal is tracking health, workouts, and daily tasks, the Series 12 offers the same core experience for $400 less. And for current Ultra owners, the Ultra 4 serves as a reason to appreciate—and stick with—the generation you already have. Fortunately, there are no price changes, but there are no new finishes either.
The Ultra 4 gets the same new Health Sensing System as the Series 12, powered by Apple’s faster S11 chip and improved optical and electrical heart rate sensors. The system now tracks heart rate every five seconds throughout the day, and it measures heart rate variability (HRV) as often as every five minutes, which is up to 24 times more frequently than its predecessor. It also logs two HRV variants: Recovery HRV, which is intended to identify daily stressors, and overall HRV, which provides broader cardiovascular context.
While both of the new Apple Watches benefit from the higher-frequency tracking, it’s probably a more meaningful upgrade for people considering the Ultra as a fitness tracker. The Ultra 4 can now provide a more comprehensive picture of how your body is recovering and responding to stress throughout the day. Overnight Vitals now compares Recovery HRV against your personal baseline, and a new daytime view lets you look through differences between your day and overnight metrics.
The standout wellness feature, though, is Readiness. It combines recent activity, sleep data, and vitals to generate a daily score from 0 to 10, along with one of four recommendations: Recover, Pace Yourself, Ready, or Go For It. The score updates throughout the day as new information comes in, so a workout or change in daytime vitals can change your recommendation. You need to wear the watch to bed for at least seven nights before it can establish enough of a baseline to produce that initial score. I have only had the luxury of a Readiness score for two days now, so I will report back in a month.
For outdoor enthusiasts or endurance athletes, a Readiness score can act like a gut check: Is today the day to push your limits, or should you take it easy? The appeal of Readiness is that it (attempts to) turn a pile of health data into something actionable. But it is still a wellness metric that doesn’t account for every factor, and it shouldn’t be used to determine whether it’s safe to exercise. I generally find Readiness scores more useful as a way to track patterns over time than as a daily directive about whether I should work out.
Apple is also bringing Audio Intelligence features to the Ultra 4, including Live Rewind and Siri Recap, though those are arriving later this year. A redesigned Health app with additional longevity insights is also coming later. Simply put, some of the Apple Watch’s most interesting software changes aren’t actually available at launch.
Where the Ultra 4 has a clear advantage over its predecess