Apple announced Apple Watch Series 12 on September 9, 2026, introducing an all‑new Health Sensing System built around the S11 chip. According to the press release, the system combines new optical and electrical heart sensors with larger, power‑efficient green LEDs that measure heart rate every five seconds all day, which Apple says provides the most accurate heart rate sensing in a wearable. A scientifically rigorous study of over 1,000 participants compared this sensing against leading wearables and found Apple Watch showed the highest accuracy across devices. Heart rate variability (HRV) is now measured up to 24 times more often, with two variants: recovery HRV for daily stress and recovery signals, and overall HRV for broader cardiovascular insights. Overnight vitals include recovery HRV measured against a personal baseline, and a new daytime vitals view lets users toggle between overnight and daytime metrics. The watch also introduces a readiness score, a 0‑10 metric that analyzes recent activity, training load, vitals, and sleep score to give a clear recommendation—Recover, Pace Yourself, Ready, or Go For It. Apple said the scoring algorithm was developed using data from the Apple Heart and Movement Study in collaboration with exercise scientists and physicians. Readiness updates throughout the day as new data arrives, highlighting which factors drive the score. Battery performance sees up to 24 hours of everyday use and up to 10 hours during an outdoor workout—25 percent more than the previous model. Fifteen minutes of charging now yields up to 12 hours of additional battery life, a 50 percent improvement over the prior generation. Step tracking has been redesigned with new machine‑learning algorithms, and Apple claims the Series 12 offers the most accurate step tracking of any smartwatch, complemented by a new Steps complication for real‑time tracking on the watch face. Audio Intelligence features, arriving later this year, will help users remember key moments from conversations and stay alert to important sounds, built with privacy, security, and accessibility at the core. watchOS 27 brings Siri AI to the wrist via Apple Intelligence, providing personal context understanding and broad world knowledge. The device is offered in dark bronze, black, light gold, and space‑gray aluminum; radiant gold and natural titanium; and ceramic pearl white and night blue. Aluminum models feature Ceramic Shield 2, described as tougher than any smartwatch glass and 60 percent tougher than the Ion‑X of previous aluminum models. Apple Watch Series 12 is available for pre‑order today, with general availability beginning Friday, September 18. Kaiann Drance, Apple’s vice president of Worldwide Apple Watch Product Marketing, said, “Apple Watch Series 12 is the most advanced health and fitness companion we’ve ever created… With our new Health Sensing System and S11 chip, Apple Watch Series 12 gives you meaningful insights, like readiness, so you can better understand how to take on your day and care for your health, plus intelligence features that make everyday life easier. And it’s all wrapped in a beautifully thin, light design you’ll love wearing all day and night.”
