Apple Watch Ultra 3 / Apple Watch Series 9 (45 mm, GPS, aluminium)

Ultra 3 is sold only as a 49 mm GPS + Cellular watch; bands fit 130–210 mm wrists.

Apple says the wide-angle OLED pixels emit light at wider angles, so the screen stays readable without fully turning the wrist. LTPO3 allows thinner borders and lets the always-on mode refresh once per second, so a seconds hand is visible without raising the wrist. The 1-nit minimum reduces glare in the dark.

LTPO is a panel technology that can lower the refresh rate dramatically, letting the display stay dimly on when the wrist is down. The 1-nit minimum avoids glare in a dark room.

RedCap is a reduced form of 5G for low-data devices such as watches. Satellite connectivity lets you call for emergency help and send short messages outside cellular coverage; Apple says Find My shares location via satellite every 15 minutes. Satellite services are free for two years from activation; Find My and Messages need a carrier plan, and availability varies by region.

Using L1 and L5 together helps reduce reflected-signal errors near tall buildings and under tree cover. Ultra Wideband availability varies by region.

The electrical heart sensor powers the ECG app; the optical sensor drives heart rate and Apple’s hypertension notifications. Hypertension notifications passively analyse 30-day periods and are not intended for people under 22, during pregnancy or for those already diagnosed. The temperature sensor is not for medical use; the Blood Oxygen app is for wellness use.

Diving needs a compatible third-party app; the depth gauge is accurate to ±1 m. MIL-STD 810H covers altitude, high/low temperature, temperature shock, immersion, freeze/thaw, ice and freezing rain, shock and vibration. Passing these tests does not mean the watch cannot be damaged.

Suitable for swimming. Ion-X is the strengthened glass used on aluminium cases; steel cases use sapphire crystal.

Apple says 15 minutes of charging gives 12 hours of normal use and 5 minutes gives 8 hours of sleep tracking. Apple’s 80% in 45 minutes figure is based on its 20 W USB-C power adapter. Low Power Mode is rated at 20 hours of continuous outdoor workout with full GPS and heart rate.

Fast charging requires Apple’s fast-charging cable and a suitable adapter.

The siren helps people nearby locate a user who is lost or needs help.

The watch does not pair with Android phones; setup and most features require an iPhone.

Double tap lets you answer notifications or calls by tapping the thumb and index finger of the watch hand together twice, without touching the screen.

The electrical sensor is for ECG recordings; the optical sensor measures pulse with light. Temperature sensing tracks overnight changes in wrist temperature.

The watch collects sensor data, the paired iPhone calculates the value and shows it in the Health app. Watches bought outside the US are not affected.

It is a single-frequency (L1) receiver; drift in cities can be more likely than with dual-frequency watches.

Ultra Wideband lets you locate an iPhone 15-family phone with Precision Finding showing direction and distance; availability varies by region.

It cannot be used with Android phones.