Apple Watch Series 12 Hits Stores With Big Health Upgrades and Smarter AI

Apple’s latest wearables, the Apple Watch Series 12 and the higher‑end Ultra 4, are officially on sale as of September 18. Early hands‑on reviews say the Series 12 doesn’t look radically different from last year’s watch, but the biggest changes are hidden underneath. Apple has redesigned the rear sensor array into a new “Health Sensing System” with more densely packed LEDs and photodiodes, enabling more frequent and accurate readings for metrics like heart‑rate variability.

Inside, a new S11 chip powers watchOS 27, which leans harder on AI‑driven insights than previous versions. One headline addition is a Readiness Score that combines sleep, activity, and cardiovascular data into a simple daily indicator of how prepared your body is for strain. Reviewers also highlight faster performance and improved battery life compared to Series 11, with Ultra 4 adding features like longer endurance and expanded blood‑pressure tracking.

In the US, Series 12 keeps the same $399 starting price as its predecessor, while Ultra 4 starts higher for outdoor and performance‑focused users. For anyone upgrading from a much older Apple Watch—or buying into the ecosystem for the first time—this year’s models are being described as some of the most “future‑proof” yet, largely because the new sensor hardware gives Apple room to roll out additional health features in software over the next few years.