| Price | $139 | $169 | $199 | $169 (on sale) | $179 | $279 ($329 for metal bezels) |
| Product Announcement Date | May 5, 2014 | Sept 1st, 2016 | Apr 30th, 2019 | January 5th, 2015 | Sept 25th, 2014 | August 10th, 2017 |
| Actual Availability/Shipping Date | May/June 2014 | Sept 2016 | Early May 2019 | March 2015 | October 2014 | August 30th, 2017 |
| GPS Recording Functionality | Yes | Yes | Yes | Yes | Yes | Yes |
| Data Transfer | USB | USB, Bluetooth Smart | USB, Bluetooth Smart | USB, BLUETOOTH SMART | USB, BLUETOOTH SMART | USB & Bluetooth Smart |
| Waterproofing | 50 meters | 50 meters | 50 meters | 50 meters | Yes - 30m | Yes - 50 meters |
| Battery Life (GPS) | 8 hours | | 13 Hours | 10 hours GPS on | 8 hours | Up to 30 hours |
| Recording Interval | SMART RECORDING (VARIABLE) | SMART RECORDING (VARIABLE) | SMART RECORDING (VARIABLE) | Smart Recording (Variable) | 1-second | Variable |
| Alerts | Sound/Visual | Sound/Visual/Vibrate | Sound/Visual/Vibrate | Vibrate/Visual | Sound/Visual | Visual/Vibrate |
| Backlight Greatness | OK | Great | Great | Good | Great | Great |
| Ability to download custom apps to unit/device | No | No | Watchfaces only | Yes | No | No |
| Acts as daily activity monitor (steps, etc...) | Yes | Yes | Yes | Yes | Yes | Yes |
Music | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Can control phone music | No | Yes | Yes | Yes | No | No |
| Has music storage and playback | No | No | No | No | No | No |
| Streaming Services | | | No | | | |
Payments | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Contactless-NFC Payments | | | No | | | |
Connectivity | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Bluetooth Smart to Phone Uploading | No | Yes | Yes | Yes | Yes | Yes |
| Phone Notifications to unit (i.e. texts/calls/etc...) | No | Yes | Yes | Yes | Yes | Yes |
| Live Tracking (streaming location to website) | No | Yes | Yes | Yes | No | No |
| Group tracking | | No | No | | No | No |
| Emergency/SOS Message Notification (from watch to contacts) | No | No | Yes (via phone) | No | No | No |
| Built-in cellular chip (no phone required) | No | No | No | No | No | No |
Cycling | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Designed for cycling | BARELY (SPEED MODE ONLY) | Yes | Yes | Yes | Yes | Yes |
| Power Meter Capable | No | No | No | With some Connect IQ apps (but cannot record data) | No | Yes |
| Power Meter Configuration/Calibration Options | N/A | N/A | N/A | N/A | N/A | Yes |
| Power Meter TSS/NP/IF | N/A | N/A | N/A | N/A | N/A | No |
| Speed/Cadence Sensor Capable | No | Yes | Yes | Yes | No | Yes |
| Strava segments live on device | No | No | No | No | No | No |
| Crash detection | | No | Yes | | No | No |
Running | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Designed for running | Yes | Yes | Yes | Yes | Yes | Yes |
| Footpod Capable (For treadmills) | Yes | YES (ALSO HAS INTERNAL ACCELEROMETER) | YES (ALSO HAS INTERNAL ACCELEROMETER) | YES (Also has INTERNAL ACCELEROMETER) | Yes | Yes |
| Running Dynamics (vertical oscillation, ground contact time, etc...) | No | No | No | No | No | No |
| Running Power | | | No | | | |
| VO2Max Estimation | No | No | Yes | No | Sorta | Yes |
| Race Predictor | No | No | No | No | Can estimate finish time during race | No |
| Recovery Advisor | No | no | no | No | No (only if you have V800 too) | Yes |
| Run/Walk Mode | Yes | Yes | Yes | Yes | No | No |
Swimming | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Designed for swimming | NO (PROTECTED THOUGH JUST FINE) | NO (PROTECTED THOUGH JUST FINE) | NO (PROTECTED THOUGH JUST FINE) | Yes | No | Yes |
| Openwater swimming mode | N/A | N/A | N/A | No | No | Yes |
| Lap/Indoor Distance Tracking | N/A | N/A | N/A | Yes | N/A | Yes |
| Record HR underwater | N/A | N/A | N/A | No | No | Yes |
| Openwater Metrics (Stroke/etc.) | N/A | N/A | N/A | No | N/A | Yes |
| Indoor Metrics (Stroke/etc.) | N/A | N/A | N/A | Yes | N/A | Yes |
| Indoor Drill Mode | N/A | N/A | N/A | No | N/A | No |
| Indoor auto-pause feature | N/A | N/A | N/A | No | N/A | No |
| Change pool size | N/A | N/A | N/A | Yes | N/A | YEs |
| Indoor Min/Max Pool Lengths | N/A | N/A | N/A | 17M/18Y TO 150Y/M | N/A | 15m/y to 1,200m/y |
| Ability to customize data fields | N/A | N/A | N/A | Yes | Yes | Yes |
| Captures per length data - indoors | N/A | N/A | N/A | Yes | N/A | Yes |
| Indoor Alerts | N/A | N/A | N/A | Yes | N/A | No |
Triathlon | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Designed for triathlon | No | No | No | No | No | Yes |
| Multisport mode | N/A | No | No | No | No | Yes |
Workouts | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Create/Follow custom workouts | No | No | Yes | No | Yes | No |
| On-unit interval Feature | No | Yes | Yes | No | Yes | Yes |
| Training Calendar Functionality | No | No | Yes | No | Yes | Yes |
Functions | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Auto Start/Stop | Yes | Yes | Yes | Yes | Yes | Yes |
| Virtual Partner Feature | Pace Alerts | Virtual Pacer | Virtual Pacer | No | Via Race Estimator | No |
| Virtual Racer Feature | No | No | No | No | No | No |
| Records PR's - Personal Records (diff than history) | Yes | Yes | Yes | Only on Garmin Connect | Yes | No |
| Tidal Tables (Tide Information) | No | No | No | No | No | No |
| Weather Display (live data) | No | Yes | Yes | Via Connect IQ app | No | No |
Navigate | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Follow GPS Track (Courses/Waypoints) | No | No | No | No | No | Yes |
| Markers/Waypoint Direction | No | No | No | No | No | Yes |
| Routable/Visual Maps (like car GPS) | No | No | No | No | No | No |
| Back to start | No | No | No | Yes | Yes | Yes |
| Impromptu Round Trip Route Creation | No | No | No | No | No | No |
| Download courses/routes from phone to unit | No | No | No | No | No | Yes |
Sensors | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Altimeter Type | None | No | No | GPS | GPS | GPS |
| Compass Type | N/A | None | None | GPS | GPS | N/A |
| Optical Heart Rate Sensor internally | No | Yes | Yes | No | No | Yes |
| SpO2 (aka Pulse Oximetry) | | | No | | | |
| Heart Rate Strap Compatible | Yes | Yes | Yes | Yes | Yes | Yes |
| ANT+ Heart Rate Strap Capable | Yes | Yes | Yes | Yes | No | No |
| ANT+ Speed/Cadence Capable | No | Yes | Yes | Yes | No | No |
| ANT+ Footpod Capable | Yes | Yes | Yes | Yes | No | No |
| ANT+ Power Meter Capable | No | No | No | No | No | No |
| ANT+ Lighting Control | No | No | No | No | No | No |
| ANT+ Bike Radar Integration | No | No | No | No | No | No |
| ANT+ Trainer Control (FE-C) | No | No | No | No | nO | No |
| ANT+ Remote Control | No | No | No | Yes for Garmin VIRB | No | No |
| ANT+ eBike Compatibility | No | No | No | No | No | No |
| ANT+ Gear Shifting (i.e. SRAM ETAP) | | No | No | No | No | No |
| Shimano Di2 Shifting | No | No | No | No | No | No |
| Bluetooth Smart HR Strap Capable | No | No | No | No | Yes | Yes |
| Bluetooth Smart Speed/Cadence Capable | No | No | No | no | No | Yes |
| Bluetooth Smart Footpod Capable | No | No | No | No | Yes | Yes (+ Stryd Running Power Meter) |
| Bluetooth Smart Power Meter Capable | No | No | No | No | No | Yes |
| Temp Recording (internal sensor) | No | No | No | No | No | No |
| Temp Recording (external sensor) | No | No | No | Yes (Tempe) | No | No |
Software | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | PC Application | Garmin Express | Garmin Express (PC/Mac) | Garmin Express (PC/Mac) | Garmin Express | Polar Flowsync | PC/Mac |
| Web Application | Garmin Connect | Garmin Connect | Garmin Connect | Garmin Connect | Polar Flow | Suunto Movescount |
| Phone App | Garmin Connect Mobile | iOS/Android | iOS/Android | iOS/Android/Windows Phone | iOS/Android | iOS/Android |
| Ability to Export Settings | No | No | No | No | No | No |
Purchase | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Amazon | Link | Link | Link | Link | Link | Link |
| Backcountry.com | | | Link | | | |
| Competitive Cyclist | | | Link | | | |
| REI | | | Link | | | |
DCRainmaker | Garmin Forerunner 15 | Garmin Forerunner 35 | Garmin Forerunner 45/45S | Garmin Vivoactive | Polar M400 | Suunto Spartan Trainer Wrist HR | | Review Link | Link | Link | Link | Link | Link | Link |