The Apple Watch Series 12 and Apple Watch Ultra 4 focus on what's underneath, headlined by a new Health Sensing System that brings some of the biggest improvements to Apple Watch health tracking in years.

Design-wise, both watches look similar to their predecessors. The Apple Watch Ultra 4 comes in the same two titanium finishes: Natural and Black. The Apple Watch Series 12 sees minor dimensional changes, with a display area about 2% smaller and a casing roughly 1mm wider, though neither is noticeable in practice.

The Apple Watch Series 12 is available in aluminum, titanium, and ceramic. Aluminum comes in Dark Bronze, Light Gold, Black, and Space Gray, now with Ceramic Shield 2 glass. Titanium is offered in Radiant Gold and Natural. Ceramic returns for the first time since the Series 5 in 2019, available in Night Blue and Pearl White.

The new Health Sensing System represents the biggest upgrade to the Apple Watch's health suite in years, with redesigned electrodes offering more contact area and redesigned photodiodes for improved sensing capabilities.