Garmin Forerunner 165 vs Instinct 3 45mm Solar
Size, specs & wrist fit compared
Which one fits you
Under 16 cm (6.3 in) round, the Instinct 3 45mm Solar's lugs overhang and the Forerunner 165's do not; the Forerunner 165 fills the wrist at 16–18 cm, the Instinct 3 45mm Solar at 17–19 cm.
What else differs
- Screen: the Forerunner 165 uses a bright AMOLED screen, the Instinct 3 45mm Solar a memory-in-pixel screen that is easy to read in sunlight and sips battery.
- Battery: 28 days for the Instinct 3 45mm Solar against 11 days for the Forerunner 165 in everyday use; 40 hours for the Instinct 3 45mm Solar against 19 hours for the Forerunner 165 with GPS on.
3.3mm thinner, the Forerunner 165 is the one that slides under a shirt cuff.
The Instinct 3 45mm Solar is 2mm wider, 3.3mm thicker and 13g heavier than the Forerunner 165.
Forerunner 165
Instinct 3 45mm Solar
Case width
43mm
45mm+2mm
Thickness
11.6mm
14.9mm+3.3mm
Weight
39g
52g+13g
Forerunner 165 or Instinct 3 45mm Solar by wrist size
| Wrist round (mm left each side) | Forerunner 165≈49.5mm lug to lug, est. | Instinct 3 45mm Solar≈51.5mm lug to lug, est. |
|---|---|---|
| 14 cm / 5.5 in | Overhangs (2.2mm over) | Overhangs (3.2mm over) |
| 15 cm / 5.9 in | Overhangs (0.6mm over) | Overhangs (1.6mm over) |
| 16 cm / 6.3 in | Bold (1.1mm) | Bold (0.1mm) |
| 17 cm / 6.7 in | Sweet spot (2.7mm) | Sweet spot (1.7mm) |
| 18 cm / 7.1 in | Sweet spot (4.3mm) | Sweet spot (3.3mm) |
| 19 cm / 7.5 in | Balanced (5.9mm) | Balanced (4.9mm) |
| 20 cm / 7.9 in | Balanced (7.5mm) | Balanced (6.5mm) |
Switch or add watches
Garmin
Forerunner 165
Garmin
Instinct 3 45mm Solar
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Battery life compared
Furthest apart in Battery saver mode, where the Instinct 3 45mm Solar lasts 3.3× as long as the Forerunner 165 (65 days against 20 days).
Forerunner 165Instinct 3 45mm Solar
Battery saver
20 days65 daysExpedition
—36 daysSmartwatch
11 days28 daysMax battery GPS
—100 hoursGPS only
19 hours40 hours +130 hoursAll systems
17 hours28 hours +50 hoursAll systems + multi-band
—24 hours +40 hours
Amber figures are the solar-assisted runtime the manufacturer publishes for that mode.
More comparisons
2D Dimension Schematics
- Garmin Forerunner 165 43mm × ≈49.5mm (est.) · 11.6mm thick
- Garmin Instinct 3 45mm Solar 45mm × ≈51.5mm (est.) · 14.9mm thick
3D preview
Forerunner 165 vs Instinct 3 45mm Solar on a wrist
Specifications
The short version
7 key specs| Spec | GarminForerunner 165 | GarminInstinct 3 45mm Solar |
|---|---|---|
| Case Width | 43mm | 45mm |
| Thickness | 11.6mm | 14.9mm |
| Weight | 39g | 52g |
| Shape | Circular | Circular |
| Display type | AMOLED (optional always-on mode) | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Battery life | Smartwatch mode: Up to 11 days Battery Saver Smartwatch mode: Up to 20 days GPS-Only GNSS mode: Up to 19 hours All-Systems GNSS mode: Up to 17 hours See Details | Smartwatch: Up to 28 days/Unlimited with solar* Battery Saver Watch Mode: Up to 65 days/Unlimited with solar* GPS Only: Up to 40 hours/130 hours with solar** All Satellite Systems: Up to 28 hours/50 hours with solar** All Satellite Systems + Multi-Band: Up to 24 hours/40 hours with solar*** Max Battery GPS: Up to 100 hours/Unlimited with solar** Expedition GPS: Up to 36 days/Unlimited with solar* *Solar charging, assuming all-day wear with 3 hours per day outside in 50,000 lux conditions **Solar charging, assuming use in 50,000 lux conditions ***Solar charging, assuming use in 50,000 lux conditions; assuming typical use with SatIQ technology |
| Released | 2024 | 2025 |
Where the specifications differ
26 differences| Spec | Garmin Forerunner 165 | Garmin Instinct 3 45mm Solar |
|---|---|---|
| General | ||
| Battery life | Smartwatch mode: Up to 11 days Battery Saver Smartwatch mode: Up to 20 days GPS-Only GNSS mode: Up to 19 hours All-Systems GNSS mode: Up to 17 hours See Details | Smartwatch: Up to 28 days/Unlimited with solar* Battery Saver Watch Mode: Up to 65 days/Unlimited with solar* GPS Only: Up to 40 hours/130 hours with solar** All Satellite Systems: Up to 28 hours/50 hours with solar** All Satellite Systems + Multi-Band: Up to 24 hours/40 hours with solar*** Max Battery GPS: Up to 100 hours/Unlimited with solar** Expedition GPS: Up to 36 days/Unlimited with solar* *Solar charging, assuming all-day wear with 3 hours per day outside in 50,000 lux conditions **Solar charging, assuming use in 50,000 lux conditions ***Solar charging, assuming use in 50,000 lux conditions; assuming typical use with SatIQ technology |
| Display Size | 1.2" (30.4 mm) diameter | custom, two-window design; 0.9” x 0.9” (23 x 23 mm) |
| Lens Material | chemically strengthened glass | Power Glass™ |
| Bezel Material | fiber-reinforced polymer | fiber-reinforced polymer/aluminum |
| Memory/History | 4 GB | 128 MB |
| Display resolution | 390 x 390 pixels | 176 x 176 pixels |
| Product Info | ||
| Main SKU | 010-02863-20 | 010-02934-00 |
| Product ID | 1055469 | 1315317 |
| Product Name | Forerunner® 165 | Instinct® 3 – 45 mm, Solar |
| Release Date | 2/20/2024 | 1/6/2025 |
| Product Variation | Black/Slate Gray | Black with Black Band |
| Running Features | ||
| Ground contact time and balance | yes (but not balance) | yes (GCT balance with accessory) |
| What You'll Love | ||
| Display type | AMOLED (optional always-on mode) | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) |
| Water rating | 5 ATM | 10 ATM |
| Pulse Ox blood oxygen | yes (spot-check, during sleep, all day) | Yes |
| Battery life (smartwatch mode) | Up to 11 days | Up to 28 daysUnlimited with solar |
| Activity Profiles | ||
| Gym | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing |
| Cycling | Biking, Indoor Biking | Biking, Road Biking, Mountain Biking, Gravel Biking, Bike Commuting, Bike Touring, eBiking, eMountain Biking, Indoor Biking, Cyclocross, BMX |
| Wellness | Walking, Pilates, Yoga, Indoor Walking | Walking, Indoor Walking, Pilates, Yoga |
| Racket sports | Tennis, Pickleball, Padel | Tennis, Pickleball, Badminton, Squash, Table Tennis, Padel, Platform Tennis, Racquetball |
| Outdoor running | Running, Outdoor Track Running, Trail Running, Ultra Running | Running, Outdoor Track Running, Trail Running, Obstacle Racing |
| Outdoor recreation | Hiking | Hiking, Rucking, Indoor Climbing, Bouldering, Climbing, Hunting, Horseback Riding, Golfing, Disc Golf, Archery |
| Outdoor Recreation | ||
| Area calculation | yes (via Connect IQ™) | Yes |
| Sun and moon information | yes (via Connect IQ™) | Yes |
| Safety and Tracking Features | ||
| Live Event Sharing | Android™ Only | Yes |
| Training, Planning and Analysis Features | ||
| Respiration rate (during exercise) | Yoga and Breathwork only | yes (with compatible accessory) |
The other 149 specifications both list are identical.
Full Garmin Forerunner 165 specifications →Full Garmin Instinct 3 45mm Solar specifications →