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Apple Watch Series 3 vs Apple Watch Ultra 3

Every spec side by side, from each maker's published figures.

Better figure, where one is clearly better

AppleWatch Series 3AppleWatch Ultra 3
Overview
ReleasedSeptember 2017September 2025
Display
Case sizes38 mm or 42 mm49 mm
PanelOLEDLTPO OLED
Peak brightness1,000 nits3,000 nits
Always-on displayNoYes
Display detailRetina OLED with Force Touch; 38mm 272 x 340 pixels and 563 sq mm; 42mm 312 x 390 pixels and 740 sq mm; wake by wrist raise or tap (Wareable)Always-On Retina display with wide-angle OLEDs and LTPO3; 1Hz refresh; 422 x 514 pixels at 326 ppi; 1,245 sq mm display area; 1 nit minimum brightness; Night Mode for Ultra watch faces
Screen protectionIon-X glass on aluminium; sapphire crystal on stainless steel and ceramic (PhoneArena)Flat sapphire crystal front
Health and fitness
ECGNoYes
Blood oxygenNoYes
Skin temperatureNoYes
Sleep apnoea alertsNoYes
High blood pressure alertsNoYes
Body compositionNoNo
Fall detectionNoYes
Crash detectionNoYes
GPSSingle-bandDual-band (L1 and L5)
Water resistance50 m100 m
SensorsOptical heart sensor, barometric altimeter, accelerometer up to 16 g-forces, gyroscope and ambient light sensorElectrical heart sensor; third-generation optical heart sensor; blood oxygen sensor; temperature sensor; depth gauge to 40 m; water temperature sensor; compass; always-on altimeter (–500 m to 9,000 m); high-g accelerometer; high dynamic range gyroscope; ambient light sensor
Health featuresHeart-rate monitoring including resting and recovery measurements; alerts for elevated heart rate while inactive in watchOS 4ECG app; Blood Oxygen app; hypertension notifications; sleep apnoea notifications; irregular rhythm notifications; high and low heart rate notifications; Vitals app; sleep stages and sleep score; wrist temperature; Cycle Tracking with retrospective ovulation estimates; Medications; Mindfulness with state of mind tracking; Noise
Fitness featuresGPS, GLONASS, Galileo and QZSS; elevation gain and flights climbed; pool and open-water swimming, HIIT workouts and GymKitCustomisable Action button with Precision Start; custom workouts; Training Load and Workout Effort; customisable heart rate zones; VO2 max; Race Route; Pacer; stride length, ground contact time, cadence, power and vertical oscillation; multisport workouts; offline maps with custom route creation; elevation alerts; Backtrack; swimming with water temperature; recreational diving to 40 m with third-party dive computer apps; cycling with power meters; GymKit
Safety featuresEmergency SOSEmergency SOS and Find My via satellite; Emergency SOS; international emergency calling; Siren; Crash Detection; Fall Detection; Last Emergency Call Availability Waypoint; torch; noise monitoring; Backtrack
Battery and connections
Battery life (maker's claim)Up to 18 hoursUp to 42 hours
In low-power mode–Up to 3 days
Mobile data optionYesYes
Works withiPhoneiPhone
ChipS3S10
Storage8 GB64 GB
Battery life detailBuilt-in rechargeable lithium-ion battery; cellular performance depends on coverage and usageUp to 42 hours of normal use; up to 72 hours in Low Power Mode
ChargingUSB-A magnetic charging cable; Apple lists a USB power adapter for the cellular model onlyFast charging to 80% in about 45 minutes; 15 minutes for up to 12 hours of normal use; 5 minutes for up to 8 hours of sleep tracking
ConnectivityW2 wireless chip; Wi-Fi 802.11b/g/n at 2.4GHz; Bluetooth 4.2; cellular versions add LTE, UMTS and eSIM with a compatible carrier plan. At launch GPS required iPhone 5s and cellular iPhone 6, both with iOS 11; updated Apple support requires iPhone 6sGPS + Cellular only (model A3281) with 5G RedCap and LTE; satellite connectivity; Wi-Fi 4 (802.11n) at 2.4GHz and 5GHz; Bluetooth 5.3; second-generation Ultra Wideband chip; NFC for Apple Pay; L1 and L5 precision dual-frequency GPS (GPS, GLONASS, Galileo, QZSS and BeiDou)
Storage8 GB on GPS models; 16 GB on GPS + Cellular models–
Design
Weight (lightest version)26.7 g61.6 g
SoftwarewatchOSwatchOS
Case materialsAluminium GPS models have a composite back; cellular models have ceramic and sapphire crystal back; steel and ceramic cases sold with cellular only; water resistance under ISO 22810:2010 for shallow-water swimmingGrade 5 titanium case (100% recycled titanium) with ceramic and sapphire crystal back; water resistant to 100 m (ISO 22810:2010); EN13319 recreational diving to 40 m; IP6X dust resistant; tested to MIL-STD 810H
SizeAluminium 38mm 38.6 x 33.3 x 11.4 mm, GPS 26.7 g or cellular 28.7 g; 42mm 42.5 x 36.4 x 11.4 mm, GPS 32.3 g or cellular 34.9 g. Steel uses the same dimensions at 42.4 g and 52.8 g. White ceramic 38mm 39.2 x 34.0 x 11.8 mm, 40.1 g; 42mm 42.6 x 36.5 x 11.4 mm, 46.4 g. Weights exclude bands49 x 44 x 12 mm; 61.6 g (natural) or 61.8 g (black)
BandsSport Band or Sport Loop on aluminium; Sport Band or Milanese Loop on steel; Nike Sport Band or Nike Sport Loop on Nike+; leather and additional Sport Band on Hermès; Sport Band on Edition. Nike+ reached limited availability 5 October 2017Fits 130–210 mm wrists
ColoursSilver, Space Grey and Gold aluminium; Silver or Space Black stainless steel; White or Grey ceramicNatural or Black titanium
In the boxWatch and band, USB-A magnetic charging cable; cellular models include USB power adapter and Hermès includes an additional Sport BandApple Watch Ultra 3, strap, Apple Watch Magnetic Fast Charger to USB-C Cable (1 m)

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