Apple Watch Series 12 and Ultra 4 debut with major health sensor upgrades and on-device audio AI

By Sanket Vijayasarathy

Published On: 9 September 2026 | 23:59 IST

Apple has introduced the Apple Watch Series 12 and Apple Watch Ultra 4 alongside the iPhone 18 Pro lineup, with both watches built around a new S11 chip and what the company is calling its most significant health-sensing upgrade in years. Take a look at the Series 12 and Ultra 4 India prices, availability, and complete specifications.

Watch Series 12 and Ultra 4 India pricing and availability

Apple Watch Series 12 starts at Rs 56,900
Apple Watch Ultra 4 starts at Rs 1,09,900

Both are available to pre-order now, with in-store availability from September 18. watchOS 27 rolls out September 14 for Apple Watch Series 9 or later, Apple Watch SE 3, and Apple Watch Ultra 2 or later, requiring an iPhone 11 or later running iOS 27. Apple Intelligence and the Siri AI beta also arrive with watchOS 27 on September 14, with Siri AI initially in English and French, with support for Japanese, Korean, Portuguese, and Spanish following in October.

Show Full Article

New Health Sensing System

Apple says the new Health Sensing System improves three parts of how the watch reads the body: a larger electrode surface area for better ECG contact, redesigned photodiodes arranged in a ring for more efficient optical sensing, and larger, more power-efficient green LEDs for steadier heart rate readings during movement.

The practical result is background heart rate readings taken every 5 seconds throughout the day, and heart rate variability (HRV) sampled up to 24 times more often than before. Apple now splits HRV into two readings: Recovery HRV for spotting daily stress and recovery signals, and overall HRV for a broader read on cardiovascular health. Apple also cited a study across more than 1,000 participants comparing its heart rate sensing against other wearables, claiming Series 12 and Ultra 4 come out on top for accuracy.

This data feeds a new daily Readiness score, which factors in recent activity, training load, vitals, and sleep to give a 0-10 rating with a recommendation, ranging from “Recover” to “Go For It.” The score updates through the day as new data comes in. Apple says it developed the algorithm using data from its own Heart and Movement Study, alongside exercise scientists and physicians.

“Apple Watch Series 12 is the most advanced health and fitness companion we’ve ever created,” said Kaiann Drance, Apple’s VP of Worldwide Apple Watch Product Marketing.

Step tracking and battery

Apple has also redesigned the pedometer model with new machine learning algorithms, which it says makes Series 12 and Ultra 4 the most accurate step trackers of any smartwatch, along with a new real-time Steps watch face complication.

On battery, Series 12 continues to offer up to 24 hours of everyday use and now adds up to 10 hours during an outdoor workout, a 25 percent jump over the previous model. Charging is faster too, with 15 minutes now adding up to 12 hours of extra battery, 50 percent more than before.

Ultra 4 gets a bigger jump: Apple rates it for over two days of everyday battery life (up to 50 hours), and up to 84 hours in Low Power Mode. For workouts, the standard Extended Workout mode now covers up to 25 hours with full GPS and heart rate tracking, up 25 percent over the previous model, while the Max Extended Workout mode stretches to 45 hours, which Apple pitches as enough for a 100-mile race. Charging is faster here too, with 15 minutes adding up to 18 hours of battery.

A redesigned Health app, and Health Age

The Health app on iPhone is getting an overhaul this year, with a new Insights tab that surfaces an Apple Intelligence-generated summary of a person’s most relevant health data, along with personalised suggestions. Apple also introduced Health Age, which compares Apple Watch metrics like VO2 max and sleep, plus optional bloodwork biomarkers, against a person’s actual age. A new Longevity tab rolls sleep, movement, and heart health data into an overall health picture, and can pull in lab results manually, from synced medical records, or via an optional lab panel.

Audio Intelligence

Both watches introduce Audio Intelligence, a set of on-device features built on the S11 chip’s microphone and always-on processor:

Sound Recognition listens for sounds like sirens, alarms, doorbells, or a crying baby, and notifies the wearer even when their phone isn’t nearby, aimed particularly at people who are deaf or hard of hearing.
Live Rewind lets a user double-press the Digital Crown to instantly see the last 15 seconds of a conversation as a text snippet, with an audible chime and on-screen indicator so people nearby know it’s active.
Siri Recap uses ambient listening to generate a title and key points for a conversation, reviewable later in the Siri app. It produces a summary, not a full transcript, and is designed to exclude sensitive details like financial information or ID numbers. Users choose exactly when it runs, or can turn it off entirely from Control Center.
Shazam integration automatically identifies music playing nearby and surfaces the song and artist on a Smart Stack widget.

Apple says none of these features creates or stores audio recordings, that raw audio is processed in an isolated, hardware-separated part of the S11 chip and immediately deleted, and that Audio Intelligence does not identify or attribute individual speakers. Live Rewind text and Siri Recap summaries are end-to-end encrypted and synced via iCloud. Live Rewind and Siri Recap arrive in beta later this year, in English first.

Chip, design, and colours

Both watches run on the new S11 chip, which Apple calls its most powerful wearable chip yet, sharing CPU, GPU, and Neural Engine architecture with the A20 Pro, plus a dedicated, hardware-isolated audio processing block for Audio Intelligence.

Series 12 (42mm and 46mm) comes in dark bronze, black, light gold, and space gray aluminium, radiant gold and natural titanium, and a ceramic option in pearl white and night blue. Aluminium models get Ceramic Shield 2, which Apple says is 60 percent tougher than the previous generation’s Ion-X glass. Ultra 4 comes in natural and black titanium, with a new Hermès Grand H titanium band option and a new Fathom and Wonder watch face.

watchOS 27 also brings a dynamic Siri-suggested app grid, a new single-handed tap gesture for the Smart Stack, perimenopause and menopause support in Cycle Tracking, and Workout Buddy support without an iPhone nearby, now also in Spanish.

While Apple touts significant health upgrades, the real-world impact of the 5-second heart rate readings will be crucial for users seeking deeper insights.