Apple unveiled the Apple Watch Ultra 4 alongside the iPhone Duo and iPhone 18 Pro. While the 49mm titanium case design remains effectively identical to the Apple Watch Ultra 3, internal upgrades are significant. The Ultra 4 features a new chip enabling enhanced AI capabilities including Siri Recaps, Live Rewind, and sound recognition.

A redesigned health sensor system adds a third-generation optical heart sensor alongside the electrical heart and temperature sensors. Battery life improves to 50 hours (84 in Low Power Mode) versus 42 hours (72 in Low Power Mode) on the Ultra 3. Both models share 100-meter water resistance, Emergency SOS via Satellite, Messages via Satellite, Find My via Satellite, and a Retina LTPO3 OLED display up to 3,000 nits.

The Ultra 4 weighs slightly more at 63g (Natural Titanium) and 63.1g (Black Titanium). Both start at $799 and run on iOS 27. Satellite navigation support differs slightly, with the Ultra 4 listing GPS, Galileo, QZSS, and BeiDou while the Ultra 3 includes GLONASS.