Apple Watch Ultra 3 / Samsung Galaxy Watch5 Pro (45 mm)

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 bezel is raised above the display, which Samsung designs to protect the glass from knocks. There is no rotating bezel; menus are navigated with touch gestures and the buttons.

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.

Electrical Heart Signal enables ECG and Bioelectrical Impedance enables body composition estimates; ECG works through the Samsung Health Monitor app only in approved markets.

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.

5ATM covers surface water use such as swimming, not diving or high-pressure water. MIL-STD-810H is the US military standard for environmental test methods.

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.

Samsung says real battery life varies with network environment and usage patterns. 590 mAh is about 44% larger than the 410 mAh battery in the 44 mm Galaxy Watch5.

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

Dimensions are measured without the health sensors and weight without the strap.

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

The D-buckle band folds open; because the watch cannot lie flat, it is charged on its side on the Samsung charger.

Activation requires connecting to an Android phone with Google Mobile Services; it cannot be used with an iPhone.

The LTE model can make calls and use data without the phone nearby; support depends on the carrier.