Apple Watch Series 12 Debuts With Health Sensing System and S11 Chip

Apple has introduced Apple Watch Series 12 with a new Health Sensing System, the S11 chip, a daily readiness score, and Audio Intelligence features.

Health Sensing and Readiness

New optical and electrical heart sensors measure heart rate every five seconds throughout the day, while heart rate variability can be measured up to 24 times more often. Apple says a study of more than 1,000 participants found Series 12 had the highest heart rate accuracy among the leading wearables it tested. The comparison used commercially available bestselling devices available as of June 2026.


The watch separates HRV into recovery HRV for daily stress and recovery signals and overall HRV for longer-term health insights. Overnight vitals compares recovery HRV with a user's personal baseline, while a new daytime view can surface changes before they appear in overnight data. The Vitals app is intended for wellness rather than medical use.



Readiness combines recent activity, training load, vitals, and sleep score into a 0-10 score that updates as new data arrives. Its four recommendations are Recover, Pace Yourself, Ready, and Go For It, with the watch showing which factors affected the result.

Battery, Steps, and the Health App

Series 12 retains up to 24 hours of everyday battery life and extends outdoor workout battery life to 10 hours, 25 percent longer than the previous model. A 15-minute charge provides up to 12 additional hours, a 50 percent increase. Apple's battery and charging tests used preproduction hardware and software, and actual results vary by use and configuration.

A redesigned pedometer model and the S11 chip improve indoor distance measurements and all-day step counts. Apple calls it the most accurate step tracking of any smartwatch based on a 1,000-step test validated with video counting against industry-leading smartwatches available as of July 2026. A new Steps complication displays the count on the watch face.


Arriving later this year, the redesigned Health app adds an Insights tab and a Longevity tab with Health Age, which shows how selected metrics compare with a user's age. Movement evaluations use vision-based models on iPhone together with Apple Watch heart rate data to measure flexibility, strength, and balance. In the U.S., users will also be able to order labs covering more than 50 biomarkers for $119 at about 2,000 Quest Diagnostics locations. The new app will initially be available in U.S. English on Apple Intelligence-enabled iPhone and iPad models, with some features limited to iPhone and Health Age requiring Apple Watch.

Audio Intelligence and watchOS 27

Audio Intelligence uses the watch microphone, the S11 chip, Apple Intelligence models on iPhone, and Private Cloud Compute. Sound Recognition can alert users who are deaf or hard of hearing to sounds such as sirens, alarms, doorbells, and a baby crying. Live Rewind displays the previous 15 seconds of a conversation as text after a double press of the Digital Crown, Siri Recap creates a title and key points after a conversation, and Shazam can automatically identify nearby music in the Smart Stack.

Apple says the features do not create or store audio recordings. Raw audio is processed inside the S11 chip's Secure Exclave and then deleted, while Live Rewind text and Siri Recap summaries are end-to-end encrypted in the Siri app. Live Rewind also plays an audible chime and shows an on-screen animation and microphone indicator while active. Additional Audio Intelligence privacy and system details are available from Apple Support.



Audio Intelligence requires Apple Watch Series 12 or Apple Watch Ultra 4. Live Rewind and Siri Recap are scheduled to enter beta in late 2026, require an Apple Intelligence-enabled iPhone 16 or later excluding iPhone 16e, and will launch in English outside the EU. Features that use server-side models are subject to daily usage limits.

watchOS 27 and Apple Intelligence will be available Monday, September 14. On the watch, Apple Intelligence requires an enabled device set to English, Danish, Dutch, French, German, Italian, Norwegian, Portuguese, Spanish, Swedish, Turkish, Vietnamese, simplified or traditional Chinese, Japanese, or Korean, although feature availability varies by language and region. The Siri AI beta arrives with the update, bringing personal context, broad world knowledge, a dedicated Siri app, and a Siri Modular watch face. It launches in English, with French, Japanese, Korean, Portuguese, and Spanish support due in October, and will not initially be available in the EU; server-side features may also have daily limits.

Other watchOS 27 additions include a dynamic app grid with five Siri-suggested apps, a single-handed tap gesture for opening Smart Stack widgets, perimenopause and menopause support in Cycle Tracking, and Workout Buddy without a nearby iPhone. The tap gesture requires Apple Watch Series 9 or later, Apple Watch SE 3, or Apple Watch Ultra 2 or later, while Workout Buddy requires a paired Apple Intelligence-enabled iPhone, Bluetooth headphones, English or Spanish device and Siri settings, and Wi-Fi or cellular when the phone is not nearby.

Sizes, Finishes, and Availability

The new watch comes in 42mm and 46mm sizes. Aluminum finishes include dark bronze, black, light gold, and space gray, while titanium models are offered in radiant gold and natural titanium. Aluminum cases use Ceramic Shield 2, which Apple rates as 60 percent tougher than the Ion-X glass on Apple Watch Series 11.

A ceramic version is available in pearl white and night blue. Apple Watch Hermès Series 12 adds a radiant gold titanium finish alongside silver titanium, with a Noir satin Clou de Selle band for the gold model and a new knitted Rocabar Club band.



Pre-orders are open in Australia, Canada, France, Germany, India, Japan, the UAE, the UK, the U.S., and more than 50 other countries and regions. Apple Watch Series 12 starts at $399, with retail availability beginning Friday, September 18.

The update is compatible with Apple Watch Series 9 or later, Apple Watch SE 3, and Apple Watch Ultra 2 or later. It requires iPhone 11 or later or iPhone SE (2nd generation or later) running iOS 27 or newer, and not every feature is available on every device or in every region.