The River Colne is a tributary of the River Thames in southern England, flowing approximately 58 kilometres (36 miles) through Hertfordshire, Buckinghamshire, Greater London, and Surrey. Its source lies near Brookmans Park in Hertfordshire, and it meets the Thames at Staines. No paddling licence is required to paddle the river.

The river passes through the Colne Valley Regional Park, where between Rickmansworth in the north and Denham in the south it meanders alongside and through a series of lakes, running parallel to the Grand Union Canal. This stretch offers multiple put-in options, with the Rickmansworth Aquadrome — which has a large car park — considered one of the more accessible launch points. Paddlers can combine sections of the river with the Grand Union Canal to create loop routes. The Nomad Kayak Club, based at the Rickmansworth Aquadrome clubhouse, has used the river for organised trips, paddling from the aquadrome along the canal before joining the Colne near Frogmore Wharf.

Paddlers should be aware of overhanging trees that can partially block the river in places, and weirs are present along the course. One weir in particular has been noted as a point where an open canoe overturned during a club trip, though without serious injury. The river has documented litter and debris issues; organised clean-up events have repeatedly collected significant volumes of rubbish including plastics, glass, and other waste, suggesting ongoing water quality concerns.

The river is considered accessible to both novice and experienced paddlers. The Colne Valley setting provides a mix of natural and semi-urban character, with the river threading through a landscape of lakes and parkland.