Apple Watch Series 12 and Ultra 4 Launch With New Health Sensing System

Apple has launched the Apple Watch Series 12 and Apple Watch Ultra 4, both built around a new Health Sensing System that changes how the watches track heart rate and other vitals. Both models are open for preorder now and ship on September 18, 2026.

What the Health Sensing System changes
The redesigned sensor architecture increases the electrode surface area for better ECG skin contact, arranges photodiodes in a ring for more efficient light capture, and uses larger, more power-efficient green LEDs for steadier heart rate readings during motion. Apple says the combined changes make readings more reliable during workouts, not just at rest.

Heart rate tracking, far more often
The Apple Watch Series 12 and Ultra 4 now measure heart rate every five seconds throughout the day, about 60 times more frequently than earlier models, shown through a new watch face complication. Heart rate variability sampling also increases, with separate recovery and overall HRV values displayed in a new section of the Heart Rate app.

A faster chip inside both watches
Both models share the same sensing platform and run on the S11, Apple's most powerful chip yet for a wearable device. The aluminum Apple Watch Series 12 also gains Ceramic Shield 2, which Apple says is 60 percent sturdier than the Ion-X glass used on prior aluminum generations, addressing a common complaint about scratched watch faces.

Pricing and where to buy
The Apple Watch Series 12 starts at $399, while the Apple Watch Ultra 4 starts at $799. Both are available to preorder through Apple's online store ahead of their September 18 release, with in-store availability expected the same day.

Who this update is for
The jump in heart rate sampling frequency and sensor accuracy is aimed at users tracking fitness, recovery, and cardiac health more closely, rather than a visible design overhaul. Anyone coming from a watch several generations old will notice the difference most in daily heart rate detail.

How the two models differ
The Apple Watch Ultra 4 keeps its larger case, longer battery life, and rugged titanium build for outdoor and endurance use, while the Apple Watch Series 12 stays the more compact, everyday option, with both sharing the same underlying Health Sensing System and S11 chip.

Protect your new Apple Watch Series 12 or Ultra 4 with a Komodoty band
A watch built around a more sensitive Health Sensing System deserves a band that keeps a secure, skin-safe fit through workouts and daily wear. Komodoty makes Apple Watch Series 12 and Ultra 4 bands in Alcantara and other premium materials, with precise sizing for a comfortable, secure fit. Browse the options in the Komodoty Apple Watch bands collection.