Garmin Forerunner 645
Running GPS & Heart Rate Monitors

Garmin Forerunner 645

Running GPS & Heart Rate Monitors
Unavailable to buy
NOW £249.99 Was £300.00

With Forerunner 645, every run is a performance. Fine-tune your training with wrist-based heart rate, advanced running dynamics and performance monitoring features. You can even customize your watch by downloading free watch faces, apps and more from Connect IQ. All you need in a super-lightweight, sleek design!

Delivery & Returns

UK Orders over £10: FREE

UK Standard: £2.95

UK DHL Express: £6.50

International Express: from £14

International Standard: from £12


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Running Dynamics:

Perfect your running form with detailed running dynamics like ground contact time balance, vertical ratio, stride length, running power and more (When used with running pod, HRM-Run or HRM-Tri monitor).

Garmin pay ready:

Includes Garmin Pay Ready contactless payment method lets you make convenient payments with your watch, so you can leave your cash and cards at home. - This feature is widely available in the US but in the UK it is only Danske Bank: MASTERCARD, that approves it at the moment. More banks should follow in the near future.

Training status:

A performance monitoring tool that automatically evaluates your recent exercise history and performance indicators to let you know if you’re training productively, peaking or overreaching.

Connected features (When paired with a compatible smartphone; see

Includes smart notifications plus the ability to send prewritten responses to text messages, automatic uploads to Garmin Connect and the ability for others to track your runs with the LiveTrack feature.

Connect IQ:

Get free watch faces, widgets and apps from Connect IQ so you can know when your Uber is arriving, follow your TrainingPeaks workout, find out your running power  and more.

24/7 HR monitoring:

Garmin Elevate wrist heart rate technology gives you all-day heart rate monitoring at the wrist.


Track even better in more challenging environments than GPS alone.

Wellness monitoring:

Features all-day stress tracking and relaxation-based breathing timer to help balance stress and rest.

Built-in sports:

The running sports are just the beginning, because there is also built-in support for cycling, pool swimming, row, elliptical, cardio and lots more.

Custom workouts:

Download or create your own custom running, cycling, cardio or strength workouts and download them to your watch.

Garmin CONNECT, Mobile app:

Garmin Connect is an online community where people can connect and compete by joining challenges, encourage each other’s successes and share triumphs via social media. Garmin Connect is free and available on your smartphone with the Garmin Connect Mobile app.

Battery life:

Up to 7 days in smartwatch mode and 12 hours in GPS mode. 645 Music gets up to 7 days in smartwatch mode and 5 hours in GPS mode with music.

  • Wi-Fi connectivity
  • ANT+ /USB /BLE connectivity
  • Smartphone notifications
  • Connect IQ apps
  • Wrist HR
  • Barometric altimeter
  • Activity tracking
  • Floors climbed
  • Intensity minutes
  • VIRB remote control
  • Extended timeout
  • Auto Lap / Manual lap feature
  • Configurable lap pop-up
  • Auto Pause feature
  • Alerts
  • Workouts
  • Training plans
  • Metronome
  • Pool swim activity
  • Configurable data fields
  • Aerobic training effect
  • Anaerobic training effect
  • Training Status
  • Training Load
  • VO2 max
  • Recovery time
  • Race predictor
  • Auto max HR
  • Lactate threshold
  • HRV stress test
  • Performance condition
  • Ground contact time
  • GCT balance
  • Cadence
  • Vertical oscillation
  • Stride length
  • Vertical ratio
  • Battery life: training mode - 12hours, watch mode - 7 days
  • Weight: 42.2g

Sensor Compatibility

  • Running Power
  • Bike speed and cadence
  • Running Dynamics Pod
  • Varia Vision in-sight display
  • Varia smart bike lights
  • Varia rearview radar
  • HRM-Run
Delivery & Returns

UK Orders over £10: FREE

UK Standard: £2.95

UK DHL Express: £6.50

International Express: from £14

International Standard: from £12


More Delivery Information

More Returns Information


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Delivery Information

UK Delivery is FREE on orders over £10.

International Delivery within 3 working days via DHL (prices vary according to country).

Priority First Class Delivery within 3 working days (charge £5).

Next Day Delivery available weekdays on orders placed before 3pm for next working day delivery (charge £7).

Orders placed Monday - Friday before 3pm will be dispatched the same day.

See full delivery details »

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