Apple Watch Series 6 vs Apple Watch Ultra 3

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

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Watch Series 6 compared with Watch Ultra 3

	AppleWatch Series 6	AppleWatch Ultra 3
Overview
Released
Released	September 2020	September 2025
Display
Case sizes
Case sizes	40 mm or 44 mm	49 mm
Panel
Panel	LTPO OLED	LTPO OLED
Peak brightness
Peak brightness	1,000 nits	3,000 nits (better)
Always-on display
Always-on display	Yes	Yes
Display detail
Display detail	Always-On Retina LTPO OLED; 40mm 324 x 394 pixels and 759 sq mm; 44mm 368 x 448 pixels and 977 sq mm; wrist-down outdoor brightness up to 2.5 times Series 5	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 protection
Screen protection	–	Flat sapphire crystal front
Health and fitness
ECG
ECG	Yes	Yes
Blood oxygen
Blood oxygen	Yes	Yes
Skin temperature
Skin temperature	No	Yes
Sleep apnoea alerts
Sleep apnoea alerts	No	Yes
High blood pressure alerts
High blood pressure alerts	No	Yes
Body composition
Body composition	No	No
Fall detection
Fall detection	Yes	Yes
Crash detection
Crash detection	No	Yes
GPS
GPS	Single-band	Dual-band (L1 and L5)
Water resistance
Water resistance	50 m	100 m (better)
Sensors
Sensors	Blood oxygen sensor; electrical and third-generation optical heart sensors; compass, always-on altimeter, accelerometer up to 32 g-forces, gyroscope and ambient light sensor	Electrical 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 features
Health features	ECG and Blood Oxygen apps, irregular-rhythm notifications; sleep tracking and automatic handwashing detection in watchOS 7; oxygen readings are for general wellness rather than medical use	ECG 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 features
Fitness features	GPS/GNSS and GymKit; always-on elevation tracking; dance, core training, functional strength training and cooldown workouts in watchOS 7	Customisable 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 features
Safety features	Fall detection and Emergency SOS; international emergency calling on cellular versions in supported regions	Emergency 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)
Battery life (maker's claim)	Up to 18 hours	Up to 42 hours
In low-power mode
In low-power mode	–	Up to 3 days
Mobile data option
Mobile data option	Yes	Yes
Works with
Works with	iPhone	iPhone
Chip
Chip	S6	S10
Storage
Storage	32 GB	64 GB (better)
Battery life detail
Battery life detail	Built-in rechargeable lithium-ion battery	Up to 42 hours of normal use; up to 72 hours in Low Power Mode
Charging
Charging	1 m magnetic charging cable; full charge in under 1.5 hours, according to Apple's launch announcement	Fast 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
Connectivity
Connectivity	W3 wireless chip and U1 Ultra Wideband chip; Wi-Fi 802.11b/g/n at 2.4GHz and 5GHz; Bluetooth 5.0; cellular versions add LTE and UMTS; requires iPhone 6s or later with iOS 14 at launch	GPS + 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)
Design
Weight (lightest version)
Weight (lightest version)	30.5 g (better)	61.6 g
Software
Software	watchOS	watchOS
Case materials
Case materials	Aluminium, stainless steel or titanium; ceramic and sapphire crystal back; 50 m rating under ISO 22810:2010 for shallow-water swimming	Grade 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
Size
Size	40mm 40 x 34 x 10.7 mm, aluminium 30.5 g, steel 39.7 g or titanium 34.6 g; 44mm 44 x 38 x 10.7 mm, aluminium 36.5 g, steel 47.1 g or titanium 41.3 g; case weights exclude bands	49 x 44 x 12 mm; 61.6 g (natural) or 61.8 g (black)
Bands
Bands	Apple Watch Studio offers case and band choices; Solo Loop and Braided Solo Loop introduced with Series 6; Nike and Hermès bands and faces also offered	Fits 130–210 mm wrists
Colours
Colours	Silver, Space Grey, Gold, Blue or (PRODUCT)RED aluminium; Silver, Graphite or Gold stainless steel; natural or Space Black (DLC) titanium; Nike Silver or Space Grey; Hermès steel or Space Black steel	Natural or Black titanium
In the box
In the box	Watch, band or loop and 1 m magnetic charging cable; no USB power adapter	Apple Watch Ultra 3, strap, Apple Watch Magnetic Fast Charger to USB-C Cable (1 m)