Apple Watch Series 12 & Ultra 4: Everything you need to know about the 2026 Apple Watches

Macworld In September 2026 Apple unveiled the Apple Watch Series 12 and Apple Watch Ultra 4, with both models focusing much more heavily on health monitoring, Apple Intelligence and battery efficiency than on physical redesigns. Series 12 remains Apple’s mainstream premium smartwatch, while Ultra 4 continues as the larger, tougher model aimed at endurance sports, outdoor activities and diving. Both Apple Watches went on sale on September 18. The biggest upgrade shared by both watches is Apple’s all-new Health Sensing System, which combines redesigned optical and electrical heart sensors with larger, more power-efficient green LEDs. Apple says it provides the most accurate heart-rate sensing of any wearable it tested. Background heart-rate readings are now taken every five seconds, while HRV can be measured as often as every five minutes – 60 times and 24 times more frequently respectively than on Series 11. That additional data powers another majo