Apple Watch Series 12 and Ultra 4: What’s New, Prices and Which to Buy

Apple Watch Series 12 and Apple Watch Ultra 4 were released in Australia on Friday 18 September 2026. Both are built around a new Health Sensing System. This guide covers what changed, the prices and how to choose between them. It is part of our September 2026 event coverage.

The new Health Sensing System

Apple has redesigned the sensors on the back of both watches. They use more capable optical and electrical sensors with larger, more power-efficient green LEDs, working with the new S11 chip. Apple says this gives the most accurate heart rate sensing in a wearable, based on a study it conducted itself.

The practical change is how often the watch measures. Background heart rate readings are taken every five seconds, and heart rate variability, an indicator of stress and recovery, as often as every five minutes. Apple calls this the most frequent sensing ever on an Apple Watch.

Those readings feed a new readiness score. It is designed to help you decide whether to rest or push yourself, based on recent activity, vitals and sleep. The Series 12 also lists a Vitals app, a Sleep app with a sleep score, an ECG app, a Blood Oxygen app and sleep apnoea notifications. Some health features need setup, and availability varies by country. They are not a substitute for medical advice.

Apple Watch Series 12

Series 12 comes in 42 mm and 46 mm cases, with an Always-On Retina display and 64GB of storage. There are three materials.

1. Aluminium, in Dark Bronze, Light Gold, Black and Space Grey. It now has Ceramic Shield 2, which Apple says is tougher than any smartwatch glass.
2. Titanium, in Radiant Gold and Natural, with a sapphire crystal display.
3. Ceramic, in Pearl White and Night Blue, also with sapphire crystal.

Apple rates it for up to 24 hours of normal use. Fast charging for 15 minutes gives up to 12 additional hours. It is rated WR 50M and IP6X.

Apple Watch Ultra 4

Ultra 4 is the larger, tougher model. It has a titanium case in natural or black, a sapphire crystal display and an Action button. It is rated WR100, for recreational scuba diving to 40 metres, and IP6X, and it is MIL-STD-810H tested.

Apple rates it for up to 50 hours of normal use and up to 45 hours of Max Extended Workout tracking. Fast charging for 15 minutes gives up to 18 hours of use. Satellite communications are among its safety features.

Siri AI and Audio Intelligence

With watchOS 27, Siri AI comes to Apple Watch. It needs an Apple Watch Series 9 or later, Ultra 2 or later or SE 3, with an Apple Intelligence-enabled iPhone nearby. Siri AI is a beta that works in English to start, and Apple says usage limits apply. Our Siri AI guide explains what it can do.

The S11 chip also supports Audio Intelligence: Live Rewind, Siri Recap, Shazam and Sound Recognition. Apple says some of these features arrive in beta in late 2026, so they are not available yet.

Price in Australia

Apple’s Australian prices start at:

1. Series 12 aluminium, 42 mm GPS, A$649¹.
2. Series 12 aluminium, 46 mm GPS, A$739¹.
3. Series 12 aluminium, GPS + Cellular, from A$799¹.
4. Series 12 titanium, GPS + Cellular, from A$1,249¹.
5. Series 12 ceramic, GPS + Cellular, from A$1,599¹.
6. Apple Watch Ultra 4, from A$1,349¹.

Series 12 or Ultra 4?

Choose Series 12 for everyday health, fitness and sleep tracking at the lowest price. Choose Ultra 4 if you train for long events, spend time outdoors or want the longest battery life and the toughest case.

Apple Watch Series 12 needs an iPhone 11 or later running iOS 27 or later. If you are buying a watch for a child, a GPS + Cellular model is required to use Apple Watch for Your Kids. Our guide to Apple’s child safety features covers the other controls to set up.

Using a new iPhone with your watch? See our iPhone 18 Pro guide. To get help choosing or setting up an Apple Watch, contact Your Mac Tech.

1. Prices shown are current as at September 2026.