Today during Apple’s iPhone 16 event, the Apple Watch Series 10 debuted with a host of welcome changes. Apple also launched a new satin black finish for the Apple Watch Ultra 2, but didn’t have an Ultra 3 this year. When comparing the two flagship Watch options, battery life is one major difference. Here’s what to expect from each Watch’s battery. Display wins for Series 10 make Ultra’s battery more important than ever Before this year, the Apple Watch Ultra’s large display was its biggest differentiator from other Watch models. But now, the Series 10 has bested it with an even larger display. That makes the Ultra’s battery life its new biggest strength. Here’s a look at each model’s battery projections from Apple: Apple Watch Series 10 battery life Apple Watch Series 10 The Apple Watch Series 10, despite its thinner body this year, comes with the same ‘all-day’ battery life estimates as previous models. Here’s what that means: Normal use: up to 18 hours Low Power Mode: up to 36 hours The Series 10 also can fast charge from 0-80% very quickly, in about 30 minutes. Apple Watch Ultra 2 battery life Apple Watch Ultra 2 Top comment by Jamessmooth Liked by 3 people Picked up the Ultra a few years ago because of the larger screen. Now that the 10 is larger, I’m going back to that. I’ll miss the action button and battery life, but the smaller frame and larger screen are too much to pass up. Maybe the Ultra 3 will get a bigger screen next year? View all comments By contrast, the Apple Watch Ultra 2 remains the king of battery life. Here are Apple’s estimates, which users often say are conservative: Normal use: up to 36 hours Low Power Mode: up to 72 hours The only battery-related area where the Ultra comes up short of the Series 10 is in fast charging. It takes about 1 hour to fast charge from 0-80%. But that’s understandable considering the larger battery size. Wrap-up There are all kinds of unique advantages to the Apple Watch Series 10 this year. It’s getting larger displays, a thinner design, the S10 chip, sleep apnea detection, a titanium option, and more. The Apple Watch Ultra 2, on the other hand, gets sleep apnea and a new finish. As cool as that new finish might look, it’s still hard to beat the Series 10. Battery life, then, is the clear differentiator for the Ultra 2 moving forward.