Guide
London open-water training spots
A practical guide to the best places in London to build confidence, fitness and cold-water experience before a Thames swim.
You do not need to train in the Thames itself to be ready for Swim London. London and the surrounding counties have excellent open-water venues where you can practise sighting, drafting, turns, continuous swimming and cold-water acclimatisation in a safer, supervised setting. Here are the spots we recommend most often.
Royal Docks Open Water Swim Centre
The Royal Docks is one of the most accessible year-round open-water venues in central London. A marked 400 m loop, regular water-quality testing, safety cover and a friendly community make it ideal for building weekly distance. It is brackish water, so it feels closer to a river or sea swim than a lake. Wetsuits are common in cooler months, and skins swimmers are welcome when conditions allow.
West Reservoir, Stoke Newington
West Reservoir is a large, clean lake in north-east London with a dedicated open-water swimming centre. It offers a 400 m course, organised sessions, coaching and a relaxed transition area. The flat, fresh water is perfect for working on technique and endurance without the distractions of tide or traffic. It is a favourite for triathletes and long-distance swimmers throughout the season.
Hampstead Heath Ponds
The Highgate and Hampstead ponds are iconic for cold-water acclimatisation. They are not lap pools, and they do not have marked courses, but they are unbeatable for learning how your body reacts to cold water, practising breathing control and building the mental resilience that a longer swim demands. If you plan to swim without a wetsuit at Swim London, time in these ponds is some of the best preparation you can do.
Other useful venues
- Shepperton Open Water Swim Lake — a clean, looped lake south-west of London with good parking and a welcoming club feel.
- Liquid Leisure, Datchet — a well-known open-water venue with long course options and regular race-style sessions.
- Hyde Park Serpentine Lido — a central London option for summer swimming and cold-water dips in the Lido area.
- Thames-based clubs — several established clubs run coached river sessions further upstream. They are a useful next step once you are comfortable in open water, but always check local conditions and permissions.
What to practise before Swim London
- Continuous swimming — build up to swimming your target distance without stopping or touching the bottom.
- Sighting — practise lifting your head regularly without breaking rhythm, so you can follow a river course.
- Cold-water starts — practise getting in, settling your breathing and finding your stroke in the first 200 m.
- Tow float — swim with the kit you intend to use on race day, including a bright tow float if required.
- Feeding — for the 10 km, practise taking nutrition on the move so your stomach is comfortable with it.
From the lake to the river
Training in a lake is excellent preparation, but the Thames is a tidal river. Current, navigation, water quality and commercial traffic all mean the safest way to swim it is at an organised event. If you want to understand how a Thames swim works, read our guide on whether you can swim in the Thames.