Apple Watch Ultra 3 / Samsung Galaxy Watch Ultra (47 mm, 2024)

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

According to Samsung, Grade 4 titanium is used only on the front and back cover areas of the metal frame; the rest of the frame is a mix of plastic and Grade 2 titanium.

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.

Samsung quotes 3,000 nits peak brightness for readability in sunlight. Night Mode faces switch to red tones in the dark.

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.

Health features are for general wellness, not diagnosis; some measurements depend on the market and the paired phone.

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.

10ATM means 10 minutes at 100 metres under ISO 22810; Samsung says the watch is not suitable for high-pressure water or scuba diving. IP68 covers 1.5 metres of fresh water for 30 minutes.

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.

In Exercise Power Saving some features, such as network and Bluetooth connections, may be unavailable. Durations come from Samsung’s internal lab tests.

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.

This figure is for the 2024 launch model; the Galaxy Watch Ultra (2025) version may differ.

The One UI 8 Watch update brought Watch8 features such as Running Coach, Vascular Load and Antioxidant Index.

L1+L5 dual-frequency GPS uses two satellite signals to improve location accuracy among tall buildings and trees.

The Quick Button can be mapped to start and control workouts; holding it sounds the emergency siren.