Garmin Descent™ G1 Solar vs Garmin Forerunner® 255Size, Specs & Wrist Fit Compared
The Garmin Descent™ G1 Solar and Garmin Forerunner® 255 share a near-identical 45.5mm case, so wrist presence comes down to thickness, lug-to-lug and weight.
The Garmin Forerunner® 255 is the slimmer of the two (12.9mm vs 15.2mm), so it slides under a cuff more easily.
On the wrist the Garmin Forerunner® 255 feels lighter (49g vs 66g, case only).
Specification Comparison
| Spec | GarminDescent™ G1 Solar | GarminForerunner® 255 |
|---|---|---|
| Case Width | 45.5mm | 45.6mm |
| Thickness | 15.2mm | 12.9mm |
| Weight | 66g | 49g |
| Shape | Circular | Circular |
| GPS | Yes | Yes |
| Battery Life | Dive Mode: Up to 25 hours Smartwatch: Up to 21 days/4 months with solar * Battery Saver Watch Mode: Up to 48 days/Unlimited with solar* GPS: Up to 26 hours/39 hours with solar ** Max Battery GPS Mode: Up to 56 hours/205 hours with solar** Expedition GPS Activity: Up to 27 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 | Smartwatch mode: Up to 14 days GPS-Only GNSS mode: Up to 30 hours All-Systems GNSS mode: Up to 25 hours All-Systems GNSS mode plus Multi-Band: Up to 16 hours See Details |
| Display | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) | Sunlight-visible, transflective memory-in-pixel (MIP) |
| Released | 2023 | 2022 |
Full Specification Comparison
298 specs| Spec | Garmin Descent™ G1 Solar | Garmin Forerunner® 255 |
|---|---|---|
| Overview | ||
| Family | Garmin | Garmin |
| General | ||
| Battery life | Dive Mode: Up to 25 hours Smartwatch: Up to 21 days/4 months with solar * Battery Saver Watch Mode: Up to 48 days/Unlimited with solar* GPS: Up to 26 hours/39 hours with solar ** Max Battery GPS Mode: Up to 56 hours/205 hours with solar** Expedition GPS Activity: Up to 27 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 | Smartwatch mode: Up to 14 days GPS-Only GNSS mode: Up to 30 hours All-Systems GNSS mode: Up to 25 hours All-Systems GNSS mode plus Multi-Band: Up to 16 hours See Details |
| Display Size | custom, two-window design: 0.9” x 0.9” (23 x 23 mm) | 1.3" (33 mm) diameter |
| Case material | fiber-reinforced polymer | — |
| Lens Material | Power Sapphire | Corning® Gorilla® Glass 3 |
| Bezel Material | fiber-reinforced polymer | fiber-reinforced polymer |
| Memory/History | 32 MB | 4 GB |
| Strap material | silicone | silicone |
| Charging method | Garmin proprietary clip charger | Garmin proprietary plug charger |
| Display resolution | 176 x 176 pixels | 260 x 260 pixels |
| QuickFit® watch band compatible | yes (22 mm) | — |
| Battery type | — | Lithium ion |
| Color display | — | Yes |
| Large font option | — | Yes |
| Quick Release bands | — | yes (22 mm, Industry standard) |
| Sensors | ||
| GPS | Yes | Yes |
| Compass | Yes | Yes |
| GLONASS | Yes | Yes |
| Galileo | Yes | Yes |
| Gyroscope | Yes | Yes |
| Thermometer | Yes | Yes |
| Depth sensor | Yes | — |
| Accelerometer | Yes | Yes |
| Barometric altimeter | Yes | Yes |
| Pulse Ox Blood Oxygen Saturation Monitor | Yes | Yes |
| Garmin Elevate™ wrist heart rate monitor | Yes | Yes |
| QZSS | — | Yes |
| BeiDou | — | Yes |
| SatIQ™ Technology | — | Yes |
| Product Info | ||
| Main SKU | 010-02604-02 | 010-02641-01 |
| Product ID | 766565 | 780139 |
| Product Name | Descent™ G1 Solar | Forerunner® 255 |
| Release Date | 11/15/2023 | 6/1/2022 |
| Product Variation | Black | Tidal Blue |
| Clock Features | ||
| Timer | Yes | Yes |
| Stopwatch | Yes | Yes |
| Time/date | Yes | Yes |
| Alarm clock | Yes | Yes |
| GPS Time Sync | Yes | Yes |
| Sunrise/sunset times | Yes | Yes |
| Automatic daylight saving time | Yes | Yes |
| Diving Features | ||
| PO2 | Up to 2.0 with customizable deco PO2 setting | — |
| Tides | Yes | — |
| Backlight | yes (configurable time and intensity; auto-on at depth) | — |
| Gas mixes | Air, Nitrox and Trimix up to 100% O2; 1 bottom gas and up to 11 deco and/or backup gasses. | — |
| APNEA mode | Yes | — |
| Deep Stops | yes (using custom gradient factors) | — |
| Gauge mode | Yes | — |
| No fly time | Yes | — |
| Safety Stop | yes (customizable off/3min/5min) | — |
| Dive planner | yes (basic NDL + multi-gas deco planner) | — |
| Multi-gas mode | Yes | — |
| Nitrox support | Yes | — |
| Trimix support | Yes | — |
| APNEA hunt mode | Yes | — |
| Alerts & alarms | Audible and vibration alarms for ascent rate, PO2, CNS/OTU, NDL, deco, gas switching. Customizable (up to 40) audible and/or vibration per dive mode, based on depth or time | — |
| Single-gas mode | Yes | — |
| 3-axis dive compass | yes (with adjustable heading, quick change to 90R, 90L and reciprocal). Indicates degrees and direction back to set heading | — |
| Auto start/end dive | Yes | — |
| Decompression model | Bühlmann ZHL-16c with gradient factors | — |
| Missed Deco Lockout | yes (can be disabled prior to dive with user acknowledgement) | — |
| Custom end-dive timeout | yes (20s to 10 m) | — |
| Custom dive data screens | Yes | — |
| Customizable conservatism | yes (low/medium/high or custom using gradient factors) | — |
| Surface diver status widget | yes (surface interval, N2/HE loading, CNS, OTU and tissue compartment status) | — |
| Automatic altitude adjustment | Yes | — |
| Residual Tissue Loading Reset | yes (on the surface with user acknowledgement) | — |
| Closed Circuit Rebreather (CCR) | Yes | — |
| Dive ascent/descent rate indicator | Yes | — |
| Dive activity maximum operating depth | 100 meters | — |
| Sync dive log to Garmin Dive™ Mobile app | Yes | — |
| Automatically saves dive entry and exit locations | Yes | — |
| Boating Features | ||
| Available Boating Profiles | Boating | — |
| Built-in barometer and tide tables | Yes | — |
| Cycling Features | ||
| Courses | Yes | Yes |
| MTB Grit & Flow | Yes | — |
| Race an activity | Yes | Yes |
| Power meter compatible | Yes | Yes |
| Compatible with Varia™ lights | Yes | Yes |
| FTP (Functional Threshold Power) | Yes | — |
| Speed and cadence sensor support (w/sensor) | Yes | Yes |
| Bike lap and lap maximum power (with power sensor) | Yes | Yes |
| Compatible with Varia™ radar (rear-facing radar) | Yes | Yes |
| Compatible with Vector™ and Rally™ (power meters) | Yes | Yes |
| Alerts (triggers alarm when you reach goals including time, distance, heart rate or calories) | Yes | Yes |
| Compatible with Varia Vision™ (head-mounted display) | — | Yes |
| Golfing Features | ||
| PinPointer | Yes | — |
| Tournament legal | Yes | — |
| Digital scorecard | Yes | — |
| Garmin AutoShot™ | Yes | — |
| Round timer/odometer | Yes | — |
| Auto CourseView updates | Yes | — |
| Yardage to layups/doglegs | Yes | — |
| Hazards and course targets | Yes | — |
| Pairs with Garmin Golf app | Yes | — |
| Green View with manual pin position | Yes | — |
| CT10 Automatic club tracking compatible (requires accessory) | Yes | — |
| Yardage to F/M/B (distance to front, middle and back of green) | Yes | — |
| Stat tracking (strokes, putts per round, greens and fairways hit) | Yes | — |
| Measures shot distance (calculates exact yardage for shots from anywhere on course) | manual | — |
| Running Features | ||
| Run workouts | Yes | Yes |
| Race predictor | Yes | Yes |
| Foot pod capable | Yes | Yes |
| Running dynamics | yes (with compatible accessory) | Yes |
| Lactate threshold | yes (with compatible accessory) | Yes |
| Trail run auto climb | Yes | Yes |
| Performance condition | Yes | Yes |
| Stride length (real time) | yes (with compatible accessory) | Yes |
| Vertical oscillation and ratio | yes (with compatible accessory) | Yes |
| Ground contact time and balance | yes (with compatible accessory) | Yes |
| GPS-based distance, time and pace | Yes | Yes |
| Cadence (provides real-time number of steps per minute) | Yes | Yes |
| Running power | — | Yes |
| Grade-adjusted pace | — | Yes |
| Run/Walk/Stand detection | — | Yes |
| PacePro™ Pacing Strategies | — | Yes |
| Course- and weather-specific race predictor | — | Yes |
| What You'll Love | ||
| Display type | Monochrome, sunlight-visible, transflective memory-in-pixel (MIP) | Sunlight-visible, transflective memory-in-pixel (MIP) |
| Water rating | Dive (100 meters) | 5 ATM |
| Garmin Pay™ | Yes | Yes |
| Solar Charging | Yes | — |
| Training status | Yes | yes (improved) |
| Pulse Ox blood oxygen | yes (spot-check, during sleep, all day) | yes (spot-check, and optional all-day acclimation and in sleep) |
| Sleep score and insights | Yes | Yes |
| Battery life (smartwatch mode) | Up to 21 days4 months with solar | Up to 14 days |
| Multi-band GPS | — | Yes |
| Activity Profiles | ||
| Gym | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing | Strength, HIIT, Cardio, Elliptical Training, Stair Stepping, Floor Climbing, Indoor Rowing, Jump Roping |
| Swim | Pool Swimming, Open Water Swimming | Pool Swimming, Open Water Swimming |
| Cycling | Biking, Road Biking, Mountain Biking, Gravel Biking, Bike Commuting, Bike Touring, eBiking, eMountain Biking, Indoor Biking | Biking, Mountain Biking, eBiking, eMountain Biking, Indoor Biking |
| Wellness | Walking, Pilates, Yoga | Walking, Pilates, Yoga, Indoor Walking |
| Multisport | Swimming/Running | Triathlon |
| On the Water | Stand Up Paddleboarding, Rowing, Kayaking, Surfing, Kiteboarding, Windsurfing, Fishing, Boating | Stand Up Paddleboarding, Rowing |
| Racket sports | Tennis | Tennis, Pickleball, Badminton, Squash, Table Tennis, Padel, Platform Tennis, Racquetball |
| Snow & winter | Skiing, Snowboarding, XC Classic Skiing, Snowshoeing | Skiing, Snowboarding, XC Classic Skiing |
| Indoor running | Treadmill Running, Indoor Track Running | Treadmill Running, Indoor Track Running, Virtual Running |
| Outdoor running | Running, Trail Running | Running, Outdoor Track Running, Trail Running, Ultra Running |
| Outdoor recreation | Hiking, Indoor Climbing, Bouldering, Climbing, Hunting, Horseback Riding | Hiking, Bouldering, Archery |
| Other activity profiles | Tactical | Inline skating |
| In the ring | — | Boxing, Mixed Martial Arts |
| Team sports | — | Basketball, Volleyball, Field Hockey, Ice Hockey, Football/Soccer, American Football, Lacrosse, Rugby, Ultimate Disc, Cricket, Softball, Baseball |
| Swimming Features | ||
| Pool swim workouts | Yes | Yes |
| Time and distance alerts | Yes | Yes |
| Auto rest (pool swim only) | Yes | Yes |
| Drill logging (pool swim only) | Yes | Yes |
| Countdown start (pool swim only) | Yes | Yes |
| Underwater wrist-based heart rate | Yes | Yes |
| "Repeat on" rest timer (pool swim only) | Yes | Yes |
| Basic rest timer (up from 0) (pool swim only) | Yes | Yes |
| Stroke type detection (freestyle, backstroke, breaststroke, butterfly) (pool swim only) | Yes | Yes |
| Pool swim metrics (lengths, distance, pace, stroke count, swim efficiency (SWOLF), calories) | Yes | Yes |
| Open-water swim metrics (distance, pace, stroke count/rate, stroke distance, swim efficiency (SWOLF), calories) | Yes | Yes |
| Heart rate from external HRM (real-time during rests, interval and session stats during rests, and automatic heart rate download post-swim) | Yes | yes (with HRM-Swim, HRM-Pro, HRM-Pro Plus or HRM 600) |
| Critical swim speed | — | Yes |
| Pacing alerts (pool swim only) | — | Yes |
| Tactical Features | ||
| XERO™ Locations | Yes | — |
| Dual grid coordinates | Yes | — |
| Outdoor Recreation | ||
| Tides | Yes | — |
| TracBack® | Yes | Yes |
| Sight 'N Go | Yes | — |
| Back to start | Yes | Yes |
| UltraTrac mode | Yes | Yes |
| Vertical speed | Yes | Yes |
| GPS coordinates | Yes | — |
| Area calculation | Yes | — |
| Elevation profile | Yes | Yes |
| Projected waypoint | Yes | Yes |
| Total ascent/descent | Yes | Yes |
| Future elevation plot | Yes | Yes |
| Distance to destination | Yes | Yes |
| Expedition GPS Activity | Yes | — |
| Sun and moon information | Yes | Yes |
| Point-to-point navigation | Yes | Yes |
| Bread crumb trail in real time | Yes | Yes |
| Barometric trend indicator with Storm Alert | Yes | Yes |
| Up Ahead | — | Yes |
| Auto rest | — | Yes |
| Daily Smart Features | ||
| Calendar | Yes | Yes |
| Connectivity | Bluetooth®, ANT+® | Bluetooth®, ANT+® |
| Find My Phone | Yes | Yes |
| Find My Watch | Yes | Yes |
| VIRB® Remote | Yes | Yes |
| Weather forecasts | Yes | Yes |
| Smart Notifications | Yes | Yes |
| Smart trainer control | Yes | Yes |
| Smartphone compatibility | iPhone®, Android™ | iPhone® and Android™ |
| Controls smartphone music | Yes | Yes |
| Pairs with Garmin Connect™ Mobile | Yes | Yes |
| Battery saver (customizable low power watch) | Yes | Yes |
| Text response/reject phone call with text (Android™ only) | Yes | Yes |
| Connect IQ™ (downloadable watch faces, data fields and apps) | Yes | Yes |
| Stocks | — | yes (optional Connect IQ app) |
| Passcode | — | Yes |
| Garmin Share | — | Yes |
| Morning report | — | Yes |
| On-device Connect IQ™ Store | — | Yes |
| Find My Phone during GPS activity | — | Yes |
| Compatible with Garmin Messenger app | — | Yes |
| Realtime settings sync with Garmin Connect™ mobile | — | Yes |
| View images from notifications on watch (Android™ only) | — | Yes |
| Activity Tracking Features | ||
| TrueUp™ | Yes | Yes |
| Move IQ™ | Yes | Yes |
| Step counter | Yes | Yes |
| Floors climbed | Yes | Yes |
| Calories burned | Yes | Yes |
| Distance traveled | Yes | Yes |
| Intensity minutes | Yes | Yes |
| Automatic rep counting | Yes | Yes |
| Garmin Connect™ Challenges app | yes (optional Connect IQ app) | yes (optional Connect IQ app) |
| Move alerts (displays on device after a period of inactivity) | Yes | — |
| Auto goal (learns your activity level and assigns a daily step goal) | Yes | Yes |
| Workout and Training Plans | ||
| HIIT workouts | Yes | Yes |
| Yoga workouts | Yes | Yes |
| Cardio workouts | Yes | — |
| Pilates workouts | Yes | Yes |
| Strength workouts | Yes | Yes |
| Garmin Cycling Coach | Yes | Yes |
| Garmin Running Coach | Yes | Yes |
| Garmin Running Coach Experts | Yes | Yes |
| Garmin Coach - Prebuilt Cycling Plans | Yes | Yes |
| Daily Suggested Workout - Cycling (Pace and Heart Rate Based) | Yes | — |
| Daily Suggested Workout - Running (Pace and Heart Rate Based) | Yes | — |
| Garmin Coach - Strength | — | Yes |
| On-screen workout animations | — | Yes |
| On-screen workout muscle maps | — | Yes |
| Daily Suggested Workout - Cycling | — | Yes |
| Daily Suggested Workout - Running | — | Yes |
| Health & Wellness Monitoring | ||
| Sleep | Yes | yes (advanced) |
| Hydration | yes (in Garmin Connect™) | yes (in Garmin Connect™ and optional Connect IQ™ widget) |
| Breathwork | Yes | — |
| Fitness age | Yes | Yes |
| All-day stress | Yes | Yes |
| Women's health | yes (in Garmin Connect™) | yes (in Garmin Connect™ and optional Connect IQ™ widget) |
| Health snapshot | Yes | Yes |
| Respiration rate | Yes | Yes |
| Resting heart rate | Yes | Yes |
| Abnormal heart rate alerts | yes (high and low) | yes (high and low) |
| Relaxation breathing timer | Yes | Yes |
| Body Battery™ energy monitor | Yes | Yes |
| Wrist-based heart rate (constant, every second) | Yes | Yes |
| Sleep coach | — | Yes |
| Nap detection | — | Yes |
| Jet lag adviser | — | Yes |
| Breathing variations | — | Yes |
| Relaxation reminders | — | Yes |
| Safety and Tracking Features | ||
| Assistance | Yes | Yes |
| Incident Detection during select activities | Yes | Yes |
| Live Event Sharing | — | Android™ Only |
| Incident detection alert on phone for wearables | — | Yes |
| Kid Activity Tracking Features | ||
| Toe-to-Toe™ Challenges app | yes (optional Connect IQ Toe-to-Toe™ Challenges app) | yes (optional Connect IQ Toe-to-Toe™ Challenges app) |
| Training, Planning and Analysis Features | ||
| % HRR | Yes | Yes |
| % HR max | Yes | Yes |
| HR zones | Yes | Yes |
| HR alerts | Yes | Yes |
| Shortcuts | Yes | — |
| Manual lap | Yes | Yes |
| Auto max HR | Yes | Yes |
| Auto scroll | Yes | Yes |
| Finish time | Yes | Yes |
| HR calories | Yes | Yes |
| Voice alerts | Yes | Yes |
| Custom alerts | Yes | Yes |
| Physio TrueUp | Yes | Yes |
| Recovery time | Yes | Yes |
| Training load | Yes | Yes |
| VO2 Max (Run) | Yes | Yes |
| Course guidance | Yes | Yes |
| Training effect | Yes | Yes |
| Virtual Partner | Yes | Yes |
| Race an Activity | Yes | Yes |
| Advanced workouts | Yes | Yes |
| Interval training | Yes | Yes |
| VO2 Max (Trail Run) | Yes | Yes |
| GPS speed and distance | Yes | Yes |
| Improved recovery time | Yes | Yes |
| Configurable lap alerts | Yes | Yes |
| Customizable data pages | Yes | Yes |
| Unified training status | Yes | Yes |
| Touch and/or button lock | Yes | Yes |
| Activity history on watch | Yes | Yes |
| Downloadable training plans | Yes | Yes |
| Training effect (anaerobic) | Yes | Yes |
| Manual multisport activities | Yes | Yes |
| Heat and altitude acclimation | Yes | — |
| Customizable activity profiles | Yes | Yes |
| Auto Pause® automatic timer halt | Yes | Yes |
| Respiration rate (during exercise) | Yes | yes (with compatible accessory) |
| Auto Lap® interval tracking feature | Yes | Yes |
| Primary benefit (Training Effect labels) | Yes | Yes |
| Power Modes - customizable in-activity battery settings | Yes | — |
| HR broadcast (broadcasts HR data over ANT+® to paired devices) | yes (using ANT+) | Yes |
| HRV status | — | Yes |
| Load ratio | — | Yes |
| Rest timer | — | Yes |
| Race glance/widget | — | Yes |
| Training load focus | — | Yes |
| Multisport auto transition | — | Yes |
| HRM running pace and distance | — | Yes |
| Improved interval (includes open repeats, intervals data page, rest screen and auto detection) | — | Yes |
Wrist Fit
Garmin Descent™ G1 Solar
Sits best on wrists ~48–65mm wide (≈ 12.8–17.4cm circumference).
Garmin Forerunner® 255
Sits best on wrists ~48–65mm wide (≈ 12.8–17.4cm circumference).
2D Dimension Schematics
Accurate scale drawings based on case dimensions. Drag to pan, Ctrl+scroll to zoom. Works for every watch regardless of photo availability.
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Product Photos
Side-by-side product images at matched scale.
Garmin Descent™ G1 Solar (010-02604-02)
45.5mm × 45.5mm
Garmin Forerunner® 255 (010-02641-01)
45.6mm × 45.6mm
Frequently Asked Questions
Is the Garmin Descent™ G1 Solar bigger than the Garmin Forerunner® 255?
The Garmin Forerunner® 255 is bigger — 45.6mm vs 45.5mm case width.
Which fits a smaller wrist better, the Garmin Descent™ G1 Solar or the Garmin Forerunner® 255?
The Garmin Descent™ G1 Solar suits wrists around 48–65mm wide, and the Garmin Forerunner® 255 around 48–65mm. The one with the smaller lower bound is the safer pick for a small wrist.
Can I see the Garmin Descent™ G1 Solar and Garmin Forerunner® 255 side by side at true scale?
Yes — the schematics and photos above show both watches at matched scale, and our fit tool overlays each on your wrist width.
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