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MobileIQ

Head to head

Apple Apple Watch Series 12 46mmvsSamsung Galaxy Watch9 40mm

Released
2026-09-18Apple UK Newsroom — Apple Watch Series 12, retrieved 2026-09-13
Price
£419Apple UK store — Series 12 46mm aluminium GPS, retrieved 2026-09-22
Security updates until
Not published by the makerApple UK — watchOS 27 compatible models, retrieved 2026-09-22
Released
2026-08-07Samsung Newsroom UK — Galaxy Watch Ultra2 and Watch9, retrieved 2026-09-13
Price
£349Samsung UK store — Galaxy Watch9, retrieved 2026-09-13
Security updates until
Not published by the makerSamsung UK — How to update software on Galaxy Watch, retrieved 2026-09-13

0 wins for Apple Watch Series 12 46mm1 win for Galaxy Watch9 40mm2 gaps borderline0 differences you won’t notice£70 apart at RRP

Verdict: Galaxy Watch9 40mm ahead on 1 row, Apple Watch Series 12 46mm on none

On the makers’ published figures, the Galaxy Watch9 40mm wins on peak brightness (3,000 nits against 2,000 nits). 2 gaps are borderline, differences most people would not notice: weight (case only) (31.5 g against 39.5 g) for the Galaxy Watch9 40mm and battery life (maker's claim) (40 h against 24 h) for the Galaxy Watch9 40mm. The other 29 rows have no threshold or no direction to judge by, so nobody wins them.

True to scale

Apple Watch Series 12 46mm · 46 × 40 mmGalaxy Watch9 40mm · 42.7 × 40.4 mm

Case outlines from each maker’s published dimensions, drawn to scale. A round case is an ellipse at those figures; rectangular corner rounding is our drawing convention, not a measurement.

Specifications

A win is marked only where the figures can be ranked and the gap is one you could notice on the wrist. A row the site has no threshold for says whether the two differ, and that it is not ranking them. = marks the same figure on both, ≠ not ranked a difference with no ranking. Every figure carries its source.

Body

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
DimensionsDiffers, but not ranked.
46 x 40 x 9.7 mmOfficial
42.7 x 40.4 x 8.6 mmOfficial
Case size
46mmOfficial
40mmOfficial
Case shapeDiffers, but not ranked.
rectangularOfficial
roundOfficial
Weight (case only)
39.5gOfficial
31.5gOfficial

Marginal — most people won’t notice.

Case materialDiffers, but not ranked.
AluminiumOfficial
Armor AluminiumOfficial
Water ratingDiffers, but not ranked.
Water resistance 50m (swimproof) under ISO standard 22810:2010Official
5 ATM + IP68 / MIL-STD-810HOfficial

Display

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
Display typeDiffers, but not ranked.
Always-On Retina display with wide-angle OLEDs and LTPO3Official
Super AMOLED, Full Colour Always On DisplayOfficial
Display size
No verified data
1.34inOfficial
Display area
1196mm²Official
No verified data
ResolutionDiffers, but not ranked.
416 x 496Official
438 x 438Official
Peak brightness
2000nitsOfficial
3000nitsOfficialwins this row

Galaxy Watch9 40mm is ahead here, by a gap you’d notice.

Always-on displaySame.
YesOfficial
YesOfficial

Platform

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
Operating systemDiffers, but not ranked.
watchOS 27Official
Wear OS 7Official
ChipDiffers, but not ranked.
S11 SiPOfficial
Qualcomm SDW6100 (Snapdragon Wear Elite, 3nm, 5 core)Official
StorageDiffers, but not ranked.
64GBOfficial
32GBOfficial
RAM
No verified data
2GB3rd party

Battery

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
Battery life (maker's claim)
24hOfficial
40hOfficial

Marginal — most people won’t notice.

Charge to 80%
30minOfficial
No verified data
ChargingDiffers, but not ranked.
Fast-charge capable, Apple Watch Magnetic Fast Charger to USB-C CableOfficial
Fast ChargingOfficial

Health

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
SensorsDiffers, but not ranked.
Health Sensing System (third-generation electrical heart sensor, always-on optical heart sensor, blood oxygen sensor, temperature sensor), compass, always-on altimeter, high-g accelerometer, high dynamic range gyroscope, ambient light sensor, depth gauge to 6 metres, water temperature sensorOfficial
Accelerometer, Barometer, Bioelectrical Impedance Analysis Sensor, Electrical Heart Sensor, Gyro Sensor, Geomagnetic Sensor, Light Sensor, Optical Heart Rate Sensor, Temperature SensorOfficial
ECGSame.
YesOfficial
YesOfficial
Blood oxygen
YesOfficial
No verified data
Skin temperatureSame.
YesOfficial
YesOfficial
GPSDiffers, but not ranked.
Precision L1 GPS (GPS, GLONASS, Galileo, QZSS and BeiDou)Official
L1+L5 Dual-Frequency GPS (GPS, Glonass, Beidou, Galileo, QZSS)Official

Connectivity

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
Cellular modelSame.
YesOfficial
YesOfficial
Cellular model price
No verified data
£399Official
UK networks with eSIMDiffers, but not ranked.
EE, Vodafone, Three3rd party
EE, Vodafone3rd party
Wi-FiDiffers, but not ranked.
Wi-Fi 4 (802.11n)Official
802.11a/b/g/n 2.4GHz+5GHzOfficial
BluetoothDiffers, but not ranked.
5.3Official
6.0Official
NFC paymentsSame.
YesOfficial
YesOfficial

Compatibility

SpecificationApple Watch Series 12 46mmSamsung Galaxy Watch9 40mm
Works withDiffers, but not ranked.
iPhone 11 or later, including iPhone SE (2nd generation or later), with iOS 27 or laterOfficial
Android 13.0 or higher and with more than 1.5GB of memoryOfficial
CompatibilityDiffers, but not ranked.
iPhone onlyOfficial
Android; some features need a Samsung phoneOfficial
3 attributes neither watch has a sourced figure for

Strap width · Battery capacity · Blood pressure. Rows appear as sources are cited — a gap in our data, not a statement about either watch.

The pairs a buyer of either watch would also weigh. Any two watches in the catalogue can be compared from the chooser.