Apple announced the Apple Watch Ultra 4 at its 'Surprise and Shine' event in Cupertino today, bringing a meaningful internal upgrade while keeping the exterior design nearly identical to last year's Ultra 3.
The key upgrade is Apple's new S11 processor, which replaces the aging S10 chip first introduced with the Apple Watch Series 10 in 2024. The S11 is the performance foundation that will support watchOS 27's headline feature: a smarter, more capable Siri AI assistant announced at WWDC earlier this year. Apple also announced the Watch Series 12 today, which gets the same Siri AI integration.
The Ultra 4's health sensors have been upgraded as well. New electrodes improve ECG accuracy, while more power-efficient green LEDs allow for more accurate all-day heart rate measurements. The improved energy efficiency enables heart rate readings at 5-second intervals — 60 times more frequent than previous Ultra models. Heart rate variability measurements, which provide insights into stress and recovery, can now be taken every five minutes.
The hardware improvements arrive ahead of watchOS 27, which will include the redesigned app grid, battery life optimizations, and the AI-powered Siri assistant that works with always-on listening.
The Ultra 4 follows the Ultra 3, which debuted in 2025 with improved battery life, 5G connectivity on cellular models, satellite-based emergency messaging, and a slightly larger display with slimmer bezels.
Pricing and specific release date were not announced during the event.
