Garmin Varia™ RearVue 820 Rear Light & Radar for Cycling Safety and Visibility

The Garmin Varia RearVue 820 is Garmin's most advanced rear radar and light, stepping up from the Varia RVR315 with a significantly wider detection range, a more powerful integrated tail light, an intelligent brake light, and vehicle size indication — making it the most comprehensive rear safety system in the Varia range. It detects approaching vehicles from up to 175 metres behind you and delivers real-time alerts to a paired Garmin Edge computer or the Varia smartphone app, giving you meaningful advance warning to adjust your road position before traffic arrives.

The integrated tail light is a serious piece of kit in its own right: visible up to 2km away in daylight conditions, it operates in solid, flash, and day flash modes with up to 24 hours of battery life in day flash mode — enough for even the longest rides without needing to recharge mid-route. The intelligent brake light automatically activates when the device detects you decelerating, alerting drivers behind you that you're slowing — a feature that adds a meaningful layer of safety in traffic. The RearVue 820 also indicates the size of approaching vehicles and alerts you to vehicles travelling at the same speed as you, giving you a more complete picture of the traffic situation behind.

Like all Varia devices, the RearVue 820 integrates seamlessly with the full range of Garmin Edge computers — including the Edge 540, Edge 840, Edge 850, Edge 1040, and Edge 1050 — displaying vehicle alerts directly on your screen. It charges via USB-C and mounts cleanly to your seat tube or seatpost. Pair it with the Varia UT800 front light for a complete smart lighting system. Browse the full Garmin range or explore our lights collection and rear lights.

If you're deciding between the RearVue 820 and the Varia RVR315, the 820 offers a longer detection range (175m vs 140m), a more powerful tail light (2km visibility), the intelligent brake light, and vehicle size indication — making it the better choice for riders who regularly ride in traffic or at higher speeds.

What It's Good For

• Detecting approaching vehicles up to 175m behind you with real-time alerts to a paired Garmin Edge or Varia app
• Powerful tail light visible up to 2km away in daylight — solid, flash, and day flash modes
• Intelligent brake light that automatically activates when you decelerate
• Vehicle size indication and same-speed vehicle alerts for a more complete traffic picture
• Up to 24 hours battery life in day flash mode; USB-C charging
• Road and sportive riding where rear traffic awareness significantly improves safety
• Pairing with the Varia UT800 for a complete smart front-and-rear lighting system

What It's NOT Good For

• Off-road MTB use where rear vehicle traffic is not a concern
• Replacing attentive riding and road awareness — the Varia is a safety aid, not a substitute for good road craft
• Use as a front light — this is a rear-only device
• Riders on a tighter budget who don't need the extended range and brake light — the Varia RVR315 offers core radar functionality at a lower price

Frequently Asked Questions

How does the RearVue 820 differ from the Varia RVR315?
The RearVue 820 offers a longer detection range (175m vs 140m on the RVR315), a more powerful tail light visible up to 2km, an intelligent brake light, and vehicle size indication. The RVR315 is a more compact, lighter option for riders who want core radar functionality; the 820 is the better choice for riders who regularly ride in traffic or at higher speeds.

How does the intelligent brake light work?
The RearVue 820 uses its internal sensors to detect when you're decelerating and automatically activates a brake light pattern to alert drivers behind you. This happens automatically without any input from you — a genuinely useful safety feature in traffic or on descents where you're braking frequently.

Which Garmin Edge computers is it compatible with?
The Varia RearVue 820 is compatible with a wide range of Garmin Edge computers including the Edge 540, Edge 840, Edge 850, Edge 1040, and Edge 1050. It can also be used with the Varia smartphone app without a Garmin Edge computer.

Can I pair the RearVue 820 with the Varia UT800 front light?
Yes — both the RearVue 820 and the Varia UT800 can be paired simultaneously with a compatible Garmin Edge computer, giving you a complete smart front-and-rear lighting and radar system controlled from a single screen.