Apple Watch Ultra 3 / Apple Watch Series 6 (40 mm, GPS)

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.

The Always-On display keeps the time and complications visible with the wrist down.

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.

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.

The 18-hour figure comes from Apple’s August 2020 testing with pre-production watches paired to an iPhone; it varies with use.

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.

Stainless steel and titanium cases were only sold in the GPS + Cellular version. The 44 mm model uses the same chip but has a different display and weight.

Suitable for shallow-water swimming in a pool or the sea, but not scuba diving, waterskiing or high-velocity water.

Ultra Wideband availability varies by region.

Apple states Blood Oxygen measurements are not for medical use and are only designed for general fitness and wellness. The ECG app is not intended for people under 22.

On the GPS model, Emergency SOS needs the iPhone nearby; otherwise the watch must be on a known Wi‑Fi network with Wi‑Fi Calling on. International emergency calling is only on the cellular model.

LTE and UMTS are only on GPS + Cellular models.