Apple Watch Series 3Garmin Vivoactive 3
Tech specs 
Size38.6mm x 33.3mm x 10.7mm (H x W x D)
32.0mm x 35.9mm x 10.7mm (H x W x D)
43.4 x 43.4 x 11.7 mm
MaterialAluminum, Ceramic (White, Black), Sapphire Crystal, Gold Aluminium, Stainless Steel (Silver, Black)Case material: fiber-reinforced polymer and stainless steel
Lens material: Corning® Gorilla® Glass 3
Bezel material: stainless steel
Chargingwireless chargingUSB
BatteryLithium-ionRechargeable lithium-ion
Battery life18+ hoursGPS mode: Up to 13 hours
Smartwatch mode: Up to 7 days
Water-resistance5 ATM (50 metres)5 ATM
Weight53 grams43 g
SensorAmbient light, heart rate sensor, accelerometer, gyroscope, GPS, barometric altimeterGPS, barometric altimeter, compass, accelerometer, thermometer, heart rate
DisplayOLED Retina display with Force Touch
Ion-X glass (strengthened glass)
sunlight-visible, transflective memory-in-pixel (MIP), 240 x 240 pixels
Screen size38mm: 340x272 pixels
42mm: 390x312 pixels
1.2" (30.4mm) diameter
ColorsGold, Rose Gold, Space Gray, Silver, Black. Straps vary by editions.Black, White
OtherPLATFORM: watchOS
PROCESSOR: S3 dual-core processor
MEMORY: 512 RAM, 16GB storage
CONNECTIVITY: Bluetooth 4.0, NFC, WiFi, LTE and UMTS cellular radio
MEMORY: 7 timed activities, 14 days of activity tracking data
Activity tracking 
Calories burnedYesYes
Heart rateYesYes
Stress & recoveryYes
Pulse Ox
Respiration rate
UV exposure
Skin temperature
Galvanic skin response
Hydration level
Calorie intake
Running featuresWatch displays up to 5 metrics during your run (time, distance, current pace and average pace, heart rate, active calories or total calories).Preloaded running profiles, GPS based distance/time/pace, run workouts, foot pod capable
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. Preloaded swim profiles; Pool swim metrics (lengths, distance, pace, stroke count/rate, calories); Stroke type detection (freestyle, backstroke, breaststroke, butterfly); Pool swim workouts
Swim efficiency (SWOLF)
Other - gym workout tracking
- music control, find my phone, etc..
- Built in apps for running, golfing, cycling, swimming, snowboarding/skiing, paddle board, rowing, cardio, walking, strength training, rep counting, yoga, eliptical, stair-stepper and more.
Non-fitness functions 
Smartphone notificationsYesYes
On-board music storageYes ( Stream Apple Music direct to watch)
Connected payYesYes
Affiliate link*AmazonAmazon | Garmin
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