Apple Watch Series 1Apple Watch Series 2Apple Watch Series 3
Tech specs 
Size38.6mm x 33.3mm x 10.5mm (H x W x D)
32.0mm x 35.9mm x 10.5mm (H x W x D)
38.6mm x 33.3mm x 10.5mm (H x W x D)
32.0mm x 35.9mm x 10.5mm (H x W x D)
38.6mm x 33.3mm x 10.7mm (H x W x D)
32.0mm x 35.9mm x 10.7mm (H x W x D)
MaterialSteel, Aluminum, or 18k Gold (case), Sapphire CrystalSteel, Aluminum, Ceramic, Sapphire CrystalAluminum, Ceramic (White, Black), Sapphire Crystal, Gold Aluminium, Stainless Steel (Silver, Black)
Charginginductive charginginductive chargingwireless charging
BatteryLithium-ionLithium-ionLithium-ion
Battery life18 hours18+ hours18+ hours
Water-resistanceIPX7 (3 metres)5 ATM (50 metres)5 ATM (50 metres)
Weight25 grams to 69 grams depending on the model25 grams to 69 grams depending on the model53 grams
SensorAmbient light, Heart rate sensor, accelerometer, and gyroscope.Ambient light, Heart rate sensor, accelerometer, gyroscope, built-in gps.Ambient light, heart rate sensor, accelerometer, gyroscope, GPS, barometric altimeter
DisplayRetina display with Force TouchOLED Retina display with Force Touch
Ion-X glass (strengthened glass)
OLED Retina display with Force Touch
Ion-X glass (strengthened glass)
Screen size38mm: 340x272 pixels
42mm: 390x312 pixels
38mm: 340x272 pixels
42mm: 390x312 pixels
38mm: 340x272 pixels
42mm: 390x312 pixels
ColorsGold, Rose Gold, Space Gray, Silver, Black. Straps vary by editions.Gold, Rose Gold, Space Gray, Silver, Black. Straps vary by editions.Gold, Rose Gold, Space Gray, Silver, Black. Straps vary by editions.
OtherPLATFORM: watchOS
PROCESSOR: Dual-core Apple S1P
MEMORY: 8 GB, 512 MB RAM
CONNECTIVITY: WiFi, Bluetooth, NFC
PLATFORM: watchOS
PROCESSOR: Apple S2, dual-core
MEMORY: 512 RAM, 8GB storage (2GB of which can be used for music)
CONNECTIVITY: Bluetooth 4.0, NFC, WiFi
PLATFORM: watchOS
PROCESSOR: S3 dual-core processor
MEMORY: 512 RAM, 16GB storage
CONNECTIVITY: Bluetooth 4.0, NFC, WiFi, LTE and UMTS cellular radio
Activity tracking 
StepsYesYesYes
DistanceYesYesYes
CaloriesYesYesYes
ActivityYesYesYes
FloorsYes
Sleep
Heart rateYesYesYes
Vo2Max
Stress & recovery
UV exposure
Skin temperature
Galvanic skin response
GPSYesYes
Running featuresWatch displays up to 5 metrics during your run (time, distance, current pace and average pace, heart rate, active calories or total calories).Watch displays up to 5 metrics during your run (time, distance, current pace and average pace, heart rate, active calories or total calories).
Swimming featuresPool swim and open water swim. At the end of a swim, the watch displays the time of day the activity took place, dominant stroke used (auto-detection is used), distance, workout time, pool length, laps completed, average pace, average heart rate, and both active and total calories burned, as well as the weather at your location. Pool swim and open water swim. At the end of a swim, the watch displays the time of day the activity took place, dominant stroke used (auto-detection is used), distance, workout time, pool length, laps completed, average pace, average heart rate, and both active and total calories burned, as well as the weather at your location.
Smartphone notificationsYesYesYes
Other - Stream Apple Music direct to watch
Links 
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