Best rear bike lights 2025 — boost your visibility day and night with a bright beam at the back

If you're a time triallist or hill climber, or just want some brightness without adding weight to your bike set-up, then this very affordable beam from Knog is well worth a look. As well as being light on the wallet, it's also light in weight, coming in at a diddy 18g.  

Our reviewer described it as "an impressively simple light that weighs almost nothing". Pumping out 20 lumens, it's bright enough for a useful visibility boost. The mount is magnetic, and there's a USB port built into it so you don't need a cable for charging. 

Burn time is two hours in steady mode which isn't huge, but on eco flash you can get 40 hours out of it according to Knog. There are five modes to choose from, and you can't really go wrong for this price. 

The Cycliq Fly6 Pro combines a rear-facing camera and bike light, offering video recording in 4K and 100-lumen output. The video resolution is excellent for capturing details in case of an incident, and the device is easy to use with Wi-Fi transfer simplifying footage viewing. 

Compared with the Gen 3, the Pro upgrades the LED light from 50 lumens to 100 lumens and it's also a dual light system rather than the single LED on the Gen 3. There are eight different modes: camera only (rear light off), constant, flash, pulse or organic and the Fly6 Pro has an extended battery life of up to seven hours of camera recording with the light on.

We tested the bundle, which includes the Fly6 Pro, lens protector pack and silicone case, priced at £347.98. Alternatively, the Fly6 Pro is available on its own for £319.

The Lezyne Strip Pro AI Alert 400 is a very nice rear light that's easy to fit and pushes out some serious lumens for a long time, as well as packing a decent braking function.

Lezyne told us that it collected over 1,000 hours of riding data on the light, including speed, accelerometer and braking actions and fed all of that into a machine learning algorithm that tried to make sense of what braking looks like, and when the 150-lumen flashing brake light function should be activated, which tester Dave found to be effective. 

There's loads to like about the unit itself too - it's IPX7 waterproof, which is really the gold standard for a bike light, the light itself has a wide 270° field of visibility and the 400-lumen day 'highly disruptive' flash mode is really, really bright. 

The Garmin Varia RTL515 is a very good rear light with a reliable alert system for being overtaken. The radar system alerts you to cars behind you, and while you might be thinking that you don't need a radar system, Iwein felt that it made his riding safer because it alerted him to overtaking objects before he could see or hear them.

The rear light is among the best in class in terms of flash pattern and brightness too with a battery life of around 16 hours on day flash mode.

The Magicshine SeeMee 300 is cleverly designed and has a lot going for it, all without being very expensive. 

The smart mode allows the sensor on the light to monitor ambient lighting levels and adjust the light's brightness accordingly - it's optional, and there are also low, high, flash and group ride modes if you'd prefer to set it manually. The Smart Mode really is quite smart, flashing 300 lumens during the day and switching to a 100/20-lumen flash plus the OptiTracing light on a static 60 lumens. 

The mount should fit all seatposts, and our reviewer used it in all weathers and found this light very rugged and weatherproof.

The obvious comparison to the Gardia R300L would be the Garmin Varia system, and for quite a lot less money the Bryton does an impressive job of detecting cars from an impressive distance away. The beam is pretty good too. 

There are also some bonus extras, like the easy-to-use smartphone app and smart light capabilities. The unit pairs with most head units (not just Bryton) and Bryton says it can detect vehicles up to 150m away. Our reviewer found it could pick up from even further away than that, about 180-200m on long, straight roads. 

As a light it is also very effective, with five settings and just a quick press to flick between them. The light also detects changes in speed and can deploy a brake light, and a flashing light pattern that changes when a car is approaching to increase the chances of you being seen.

There are some small quirks like patchy pick-up of motorbikes and losing vehicles when they're moving at your speed, but overall this is a decent light and radar system in one. 

While it's not actually a rear light, Brightside's eponymous light deserves a mention for the clever way it provides extra visibility on top of your front and rear beams. 

Essentially, it's a well-built double-ended side light at a good price that attaches easily to your frame, and gives you an extra dimension of visibility to other road users approaching you from the side. Bright 15-lumen Cree LEDs at each end attract attention.

The Brightside has filled a gap in the market (a quick internet search only unearthed the Brightside and the Cateye Orbit Spoke lightset) in a bid to reduce the instances of SMIDSY (sorry mate I didn't see you) incidents. With too many accidents happening at junctions and roundabouts, the light is designed to give you all-round visibility to motorists approaching from your side – Brightside, not broadside.