Apple Watch Ultra 3 / Samsung Galaxy Watch6 Classic (47 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.

According to Samsung, the display is larger than on the Watch4 Classic and the rotating bezel is 15% thinner. Sapphire crystal resists scratches; the bezel partly surrounds the edge of the screen.

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.

Bioelectrical impedance analysis passes a weak current through the body when two fingers rest on the buttons to estimate muscle, fat and water; it should not be used with a pacemaker or during pregnancy. ECG and blood pressure work only in approved markets through Samsung Health Monitor.

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 corresponds to 50 metres for 10 minutes; it is not suitable for diving or high-pressure water. IP68 covers 1.5 metres in 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.

Samsung’s fast-charge testing used the magnetic fast-charging cable and a separately sold 25 W adapter. Battery life varies with network, usage and watch face.

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

Thickness is measured without the health sensors.

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

Turning the bezel moves between notifications and tiles without touching the screen; its position is sensed by a 3D Hall sensor.

Setup needs a phone with Google Mobile Services, Android 10 or later and more than 1.5 GB of memory; it does not work with an iPhone.

LTE is only on the LTE version; on the Bluetooth version internet and notifications come through the paired phone.