Apple Watch Ultra 4 / Apple Watch Series 9 (45 mm, GPS, aluminium)

Apple Watch Ultra 4: A3579; 49 mm natural titanium; translucent gray Ocean Band

Apple Watch Series 9 (45 mm, GPS, aluminium): 45 mm aluminium case, GPS model; Pink, Midnight, Starlight, Silver and (PRODUCT)RED. The 41 mm, GPS + Cellular and stainless steel (sapphire crystal) versions differ in size and materials.

SpecificationApple Watch Ultra 4Apple Watch Series 9 (45 mm, GPS, aluminium)
Release year20262023
Announcement / availability9 / 18 September 2026 Apple—
CaseGrade 5 titanium; sapphire front crystal Apple—
Size49 × 44 × 12 mm Apple—
WeightNatural titanium case 63 g Apple—
DisplayLTPO3 OLED; 422 × 514 AppleAlways-On Retina LTPO OLED; up to 2000 nits, as low as 1 nit; 326 ppi

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.

Apple
Brightness1 nit minimum; 3000 nits peak Apple—
ChipS11; dual-core 64-bit AppleS9 SiP; 64-bit dual-core processor, 4-core Neural Engine Apple
Storage64 GB Apple64 GB Apple
Health sensorsElectrical/optical heart; blood oxygen; temperature AppleElectrical heart sensor, third-generation optical heart sensor, temperature sensing

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

Apple
Outdoor sensorsDepth, water temperature, compass, altimeter Apple—
PositioningPrecision dual-frequency GNSS Apple—
WirelessWi-Fi 4, 2.4/5 GHz; Bluetooth 5.3; UWB AppleWi-Fi 4 (802.11n), Bluetooth 5.3, second-generation Ultra Wideband

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

Apple
CellularA3579: 5G RedCap and LTE Apple—
Manufacturer battery testUp to 50 hours normal use; 84 in Low Power Mode Apple—
ChargingAbout 45 minutes to 80% Apple—
Water / dust100 m rating; IP6X Apple—
Diving limitRecreational diving to 40 m Apple—
Phone compatibilityiPhone 11 / SE 2 or later; iOS 27+ Apple—
Controls—Digital Crown with haptic feedback, side button, double tap gesture

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.

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Blood Oxygen (US)—On watches sold in the US without the feature, a redesigned version arrives with iOS 18.6.1 and watchOS 11.6.1; the reading is calculated on iPhone

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.

Apple
Other sensors—Compass, always-on altimeter, high-g accelerometer, high dynamic range gyroscope, ambient light sensor Apple
Location—L1 GPS, GNSS, Galileo and BeiDou

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

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Battery and charging—Up to 18 hours normal use, up to 36 hours in Low Power Mode; fast charge to about 80% in 45 minutes

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

Apple
Durability—50 m water resistant (ISO 22810:2010); IP6X dust resistant; Ion-X front glass

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

Apple
Size and weight—45 × 38 × 10.7 mm; 38.7 g; fits 140–245 mm wrists Apple
Compatibility—iPhone XS or later with iOS 17 or later

It cannot be used with Android phones.

Apple