Garmin Forerunner 15 vs Garmin Forerunner 165

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Forerunner 15 compared with Forerunner 165

	GarminForerunner 15	GarminForerunner 165
Overview
Released
Released	2014	February 2024
Display
Case sizes
Case sizes	52 mm or 57 mm	43 mm
Panel
Panel	Memory-in-pixel	OLED
Always-on display
Always-on display	Yes	Yes
Display detail
Display detail	Monochrome memory-in-pixel display, 55 × 32 pixels; 2.1 × 2.0 cm on the small version and 2.5 × 2.4 cm on the large version, with a backlight and four-button control.	1.2-inch (30.4 mm diameter) colour AMOLED touchscreen, 390 x 390 pixels; optional always-on display; five physical buttons
Screen protection
Screen protection	–	Chemically strengthened glass
Health and fitness
ECG
ECG	No	No
Blood oxygen
Blood oxygen	No	Yes
Skin temperature
Skin temperature	No	No
Sleep apnoea alerts
Sleep apnoea alerts	No	No
High blood pressure alerts
High blood pressure alerts	No	No
Body composition
Body composition	No	No
Fall detection
Fall detection	No	No
Crash detection
Crash detection	No	No
GPS
GPS	Single-band	Single-band
Water resistance
Water resistance	50 m	50 m
Sensors
Sensors	Built-in GPS; supports a chest-worn heart-rate monitor and optional ANT+ foot pod for indoor pace and distance.	Garmin Elevate wrist heart rate; Pulse Ox; barometric altimeter; compass; accelerometer; thermometer; ambient light sensor; GPS, GLONASS and Galileo
Health features
Health features	Daily steps, calories and inactivity reminders; heart-rate recording requires the chest strap sold in some bundles.	Continuous heart rate with high/low alerts; HRV status; Body Battery; stress, respiration and blood oxygen; advanced sleep and sleep score; sleep coach and nap detection; Health Snapshot; hydration and women's health tracking; no ECG app
Fitness features
Fitness features	Outdoor pace, distance, personal records, Auto Lap, Auto Pause, Virtual Pacer and run/walk intervals; indoor distance requires the foot pod.	Daily suggested running workouts and Garmin Coach plans; training effect and recovery time; wrist-based running dynamics and running power; PacePro; VO2 max and race predictions; pool and open-water swimming; running, cycling, strength, HIIT, yoga, Pilates, tennis, pickleball and padel profiles; point-to-point and breadcrumb course navigation, back-to-start and TracBack; no full offline maps or dedicated triathlon mode; no training readiness, load or status (Wareable and Tech Advisor)
Safety features
Safety features	–	Incident detection during selected activities, assistance and LiveTrack require a paired compatible smartphone and connectivity; live event sharing is Android-only
Battery and connections
Battery life (maker's claim)
Battery life (maker's claim)	Up to 35 days	Up to 11 days
In low-power mode
In low-power mode	–	Up to 20 days
Mobile data option
Mobile data option	No	No
Works with
Works with	No phone pairing	iPhone and Android
Storage
Storage	–	4 GB
Battery life detail
Battery life detail	Up to five weeks in watch/activity-tracking mode or eight hours with GPS on.	Smartwatch up to 11 days; battery saver smartwatch up to 20 days; GPS-only up to 19 hours; all-systems GNSS up to 17 hours; actual life depends on display settings, enabled features and use
Charging
Charging	Rechargeable lithium-ion battery with a USB charging and data cable.	Garmin proprietary plug charging/data cable; rechargeable built-in battery
Connectivity
Connectivity	USB connection to a Mac or PC for Garmin Connect uploads; no Bluetooth or direct smartphone sync. ANT+ supports optional heart-rate and foot-pod accessories.	Bluetooth and ANT+ ; controls smartphone music without offline playback; no Wi-Fi; Garmin Pay; Connect IQ apps, watch faces and data fields; smart notifications; Android-only text responses and notification images; Garmin Share and Garmin Messenger; no cellular connection or multi-band GNSS
Storage
Storage	Seven activities of on-watch history.	4 GB memory/history ; standard model has no offline music player
Design
Weight (lightest version)
Weight (lightest version)	36 g (better)	39 g
Software
Software	Garmin	Garmin
Case materials
Case materials	Plastic case and band; 5 ATM water rating.	Fibre-reinforced polymer bezel; chemically strengthened glass; silicone band; 5 ATM water rating
Size
Size	Small 4.0 × 5.2 × 1.6 cm and 36 g; large 4.6 × 5.7 × 1.6 cm and 43 g. The longest case dimensions appear in the size comparison.	43 x 43 x 11.6 mm; Garmin lists 39 g without a separate body-only weight
Bands
Bands	–	20 mm quick-release silicone bands; fits 126–203 mm wrists
Colours
Colours	Small black/green, teal/white and violet/white; large black/blue and red/black.	Black/Slate Grey; Mist Grey/Whitestone
In the box
In the box	Watch, charging/data cable and manual; a chest heart-rate monitor was included in some bundles.	Forerunner 165; charging/data cable; documentation