Apple (video, MacRumors, Hacker News):

Engineered with the new Health Sensing System and S11 chip, Apple Watch Ultra 4 delivers the most accurate heart rate sensing in a wearable, higher-frequency heart rate and heart rate variability (HRV) measurements, and a new readiness score to support athletes of all kinds. Apple Watch Ultra 4 also offers extended battery life to track outdoor workouts for up to 45 hours and the most accurate on-device GPS in a sports watch.

[…]

For everyday use, Apple Watch Ultra 4 now offers more than two days of battery life, up to 50 hours. In Low Power Mode, it offers up to 84 hours of battery life. Charging is now faster than ever: Just 15 minutes adds up to 18 hours of additional battery life.

[…]

The pedometer model has been completely redesigned with new machine learning algorithms and the S11 chip to provide more accurate distance measurements during indoor walk or run workouts, and more accurate step counts all day.

[…]

Apple Watch Ultra 4 starts at $799.

pilif:

The Ultra 2 was sold to me as the watch that can do Siri without network connectivity. That was very useful to me to leave reminders for stuff I think about while on a run without the phone.

3 years later, Apple releases the OS 27 versions and Siri got improved to the point where it can’t work on-device any more on said Ultra 2

So to get the feature back which I paid for and which was specifically used to sell me the device and which now has been taken away from me, I just have to… buy the next hardware generation?

And how long will that last before they decide to remove the feature again?

Does it still work offline in the EU?

Previously:

• Audio Intelligence
• Health Sensing and Readyness
• Apple Watch Series 12
• No Siri AI in EU
• Siri AI Announced
• Dictating Literal Reminders to My Apple Watch
• Apple Watch SE 3
• Apple Watch Ultra 3
• EU iOS Envy
• Apple Watch Ultra 2
• The Disappointment of On-Device Siri

Update (2026-09-24): Adam Chandler:

The Apple Watch Ultra 4 lasted 84 hours with the screen off before I hit 15% battery life remaining. I recharged it in 90 minutes using one of my chargers (not sure if that was fast charging). That’s 3.5 days on a charge…probably could have gotten the full 4 days.

Apple Event Apple Hardware Announcement Apple Watch Apple Watch Ultra 4 Siri watchOS watchOS 27