Apple Watch Series 3 (2017)

• Display : OLED Retina display
• Processor : S3 dual core processor
• Water resistant : Up to 50 meters
• Health monitoring : Heart rate sensor
• Connectivity : GPS and GPS + Cellular models available
• Special features : First model with barometric altimeter

Apple Watch Series 4 (2018)

• Display : Larger display (over 30% larger than Series 3), LTPO OLED Retina display
• Processor : S4 with 64-bit dual-core processor
• Water resistant : Up to 50 meters
• Health monitoring : Electrical heart rate sensor (ECG app), second generation optical heart rate sensor
• Connectivity : GPS and GPS + Cellular models available
• Special features : Fall detection, improved speaker

Apple Watch Series 5 (2019)

• Display : Always-On Retina display
• Processor : S5 with 64-bit dual-core processor
• Water resistant : Up to 50 meters
• Health monitoring : ECG app, international emergency calls, fall detection
• Connectivity : GPS and GPS + Cellular models available
• Special features : Compass and altimeter always active

Apple Watch Series 6 (2020)

• Display : Always-On Retina display, 2.5x brighter outdoors when your wrist is down
• Processor : S6 with 64-bit dual-core processor (up to 20% faster than S5)
• Water resistant : Up to 50 meters
• Health monitoring : Blood oxygen sensor (SpO2), ECG app
• Connectivity : GPS and GPS + Cellular models available, U1 chip (Ultra Wideband)
• Special features : Always-on altimeter, new colours

Apple Watch SE

• Display : Retina display
• Processor : S5 with 64-bit dual-core processor
• Water resistant : Up to 50 meters
• Health monitoring : Fall detection, international emergency calls, heart rate measurements
• Connectivity : GPS and GPS + Cellular models available
• Details : Cheaper than Series 6, no ECG or blood oxygen sensor

Apple Watch Series 7 (2021)

• Display : Larger Always-On Retina display with thinner bezels, stronger and more robust front glass
• Processor : Similar CPU to Series 6
• Water resistant : Up to 50 meters
• Health monitoring : ECG app, blood oxygen sensor
• Connectivity : GPS and GPS + Cellular models available
• Features : Faster charging, improved durability, on-screen keyboard

Apple Watch Series 8 (2022)

• Display : Always-On Retina display
• Processor : New S8 chip with improved performance
• Water resistant : Up to 50 meters
• Health Monitoring : Temperature sensor for health monitoring, ECG, blood oxygen sensor
• Connectivity : GPS and GPS + Cellular models available
• Special features : Crash detection, improved sleep tracking, new colors

Apple Watch Ultra (2022)

• Display : Largest and brightest Apple Watch display
• Processor : S8 chip
• Water resistant : WR100 and EN13319 certification for diving up to 40 meters
• Health monitoring : Temperature sensor, ECG, blood oxygen sensor
• Connectivity : GPS and Cellular