Apple Watch battery life has improved significantly, with the Apple Watch Ultra 3 measuring battery life in days. The Series 11 is also notable for its extended battery performance, as of October 2, 2025.
Battery Life Improvements
In a recent battery life test, both the Apple Watch Series 10 and Series 11 achieved 28 hours between charges. This included an hour-long workout and overnight sleep tracking. This performance is a considerable advancement from the original Apple Watch, which struggled to meet its promised 18-hour battery life.
Modern Apple Watches now feature 5G connectivity and brighter displays that can always show the time, all within a thinner design. The Apple Watch Ultra can last from Monday to Thursday without needing a charge.
Software Update Requirements
Currently, Apple Watch requires at least 50% battery to install software updates, and it must be connected to a charger during the process. This precaution prevents the device from losing power mid-installation, which could render it inoperable.
With a full battery, the Apple Watch Ultra 3 can update to watchOS 26.0.2 without running out of power. This capability extends to any modern Apple Watch that has more than 50% battery.
Software updates ideally occur overnight while the watch is charging. However, the need for sleep tracking and short charging bursts complicates this process. Users often find themselves with a notification stating that an update was not installed, requiring them to manually initiate the update.
