Apple Watch Series 12 is a smartwatch in the Apple Watch product family, introduced by Apple on September 9, 2026, with retail availability beginning September 18. Its principal changes include the S11 chip, a redesigned Health Sensing System, more frequent heart measurements, and a readiness score combining activity and physiological data. Its United States launch price started at US$399. (apple.com)
Design and hardware
Series 12 is available in 42 mm and 46 mm case sizes, with aluminum, titanium, or ceramic cases. Aluminum finishes include dark bronze, light gold, black, and space gray; titanium finishes include radiant gold and natural titanium; ceramic versions come in pearl white and night blue. Aluminum models use Ceramic Shield 2 display covers, while titanium and ceramic models use sapphire crystal. (apple.com)
The watch has a wide-angle, always-on Retina display with a specified maximum brightness of 2,000 nits. Its water-related hardware includes a depth gauge operating to 6 meters and a water-temperature sensor. Apple specifies 50-meter water resistance and IP6X dust resistance. (apple.com)
Health sensing and fitness features
The Health Sensing System combines redesigned optical and electrical heart sensors with the S11 chip. Larger green light-emitting diodes support background heart-rate readings every five seconds. Heart-rate variability measurements can occur as frequently as every five minutes. The software distinguishes recovery HRV from overall HRV and incorporates recovery measurements into its Vitals interface. (apple.com)
The Readiness feature produces a score from 0 to 10 using recent activity, training load, vital measurements, and sleep score. It updates as additional information becomes available and identifies factors contributing to the result. Apple also redesigned its step-counting model using machine learning and added a watch-face complication displaying steps. (apple.com)
Other listed functions include an ECG app, high- and low-heart-rate notifications, irregular-rhythm notifications, sleep tracking, sleep-apnea notifications, and hypertension notifications. Cycle Tracking uses wrist-temperature data and includes retrospective ovulation estimates. These functions have separate availability conditions; the presence of sensors does not mean that every health feature is available in every market. (apple.com)
Software and connectivity
Series 12 runs watchOS 27. Apple lists an iPhone 11 or later running iOS 27 or later as its companion-device requirement. It is designed for the iPhone ecosystem rather than general compatibility with other smartphones. (apple.com)
GPS and GPS + Cellular configurations differ in their network capabilities. The built-in GPS records workout distance, pace, and routes without a nearby iPhone. Cellular versions support 5G and, with an appropriate service plan, can make calls, exchange messages, and stream supported audio without the paired phone nearby. (apple.com)
Siri AI and Audio Intelligence form part of its advertised software capabilities. However, Apple scheduled some Audio Intelligence functions for beta release in late 2026. A redesigned iPhone Health app, including a Health Age feature, was also scheduled for late 2026 rather than included as a fully available launch-day feature. Language, region, and compatible-device requirements apply. (apple.com)
Battery and charging
Apple rates Series 12 for up to 24 hours of normal use or 38 hours in Low Power Mode. Its fast-charging specification lists approximately 30 minutes to reach 80 percent charge, while a 15-minute charge can provide up to 12 hours of use under the stated test conditions. These figures are manufacturer ratings rather than guaranteed operating times for every usage pattern. (apple.com)