Guide · Swimming in London

Open water swimming in London

Lidos, ponds, reservoirs and docks, what the Thames rules say, how the water is tested, and how to cope with cold water.

By the London BGTC Society editorial desk · Updated 19 October 2026

At a glance

SeasonMost outdoor sites are seasonal; the Hampstead Heath ponds (except the Mixed Pond) and Parliament Hill Lido are open all year
Serpentine LidoClosed for winter after its last public swimming day on 24 September 2026
ThamesThe Port of London Authority permits swimming only upstream of Putney Bridge through to Teddington in the London area
Water qualityThe Environment Agency classifies designated sites, including the Hampstead Heath ponds and the Serpentine
Cold waterCold shock is more pronounced below 15C: get in slowly and swim with others
Last checked19 October 2026, on each operator's or official page

London has a long tradition of outdoor swimming, and if you are new to the city the choice of places can be confusing. Some are lidos and ponds with lifeguards and set hours; others are reservoirs or docks that need an induction. The River Thames is a different matter and needs its own warning. If you are building up for a triathlon, see our clubs guide and race calendar.

The Serpentine, Hyde Park

The Serpentine Lido in Hyde Park (W2 2UH) is run under The Royal Parks. According to its swimming page, the last public swimming day of the 2026 season was Thursday 24 September, and the lido is closed for winter. It is usually open daily from June to mid-September, with weekends from mid-May, though dates can vary. Booking is advisable, but walk-up is possible at quiet times. Children under 16 must be accompanied by an adult. The Serpentine Swimming Club, which describes itself as the oldest swimming club in Britain, swims daily between 5.30am and 9.30am and holds a Christmas Day race. We do not quote prices; they are on the page.

Hampstead Heath ponds and Parliament Hill Lido

The City of London runs three bathing ponds on Hampstead Heath, plus Parliament Hill Lido. Its opening times page, updated 7 October 2026, says Parliament Hill Lido, Kenwood Ladies' Pond and Highgate Men's Pond are open all year round. Hampstead Mixed Pond is open from April to October and closed to public swimming at other times. In summer there are both bookable and drop-in sessions; outside the summer period all sessions are drop-in. Bookable sessions can sell out quickly in busy periods.

The ponds' winter hours are shorter. From 25 October to 21 November 2026 they open at 7am, with last entry at 2pm. From 22 November 2026 to 13 February 2027 they open at 7.30am, with last entry at 2.30pm. Hours change through the year, so check the page before you go.

Hackney: West Reservoir and London Fields Lido

West Reservoir Centre in Woodberry Down, close to Manor House station, offers open water swimming in a natural reservoir. Its page says first-time swimmers need an induction, red swim caps are required, and sessions are booked through the Better app. Open water season dates were not stated on the page, so they are TBC - check the centre. London Fields Lido in Hackney is also run by Better; check its page for current hours.

Royal Docks

Open water swimming in the Royal Docks is run by Love Open Water. Royal Docks' own article, from 2023, says the swimming spot is at the west end of the Royal Victoria Dock pontoon, opposite City Hall, and that sessions are lifeguarded and open to competent swimmers over 10. It also says the docks are a working water environment, not open for general public swimming, and that you should enter the water only as part of an authorised activity. The operator's Royal Docks page (Dock Road, E16 1AH) said the venue was reopening in summer 2026 and told swimmers to follow its venue group for announcements. We cannot see current sessions, so availability is TBC - check the operator.

Beckenham Place Park lake

Beckenham Place Park, in the London Borough of Lewisham, describes its lake as London's first purpose-built swimming lake: 285 metres long and up to 3.5 metres deep. The lake is operated by PTP Coaching and is open for pre-booked swimming and paddle-boarding sessions. We could not find a current season or timetable on the park's page, so check with the operator before you travel.

Swimming in the Thames

The Port of London Authority (PLA) is blunt: most of the tidal Thames is not safe to swim, even for strong and experienced swimmers. It cites tides of around five miles an hour, eddies and undertows, debris, the gasp reflex in cold water, more than 600,000 ship movements a year, and sewage discharged into the river when heavy rain overwhelms the combined sewer system. In west London, swimming is permitted by the PLA upstream of Putney Bridge through to Teddington, though it says this remains a busy stretch for commercial and recreational boats.

The PLA's safety essentials include: swim with others and never alone; swim only if you are a competent open-water swimmer; plan entry and exit points; wear a high-visibility cap and use a high-visibility tow float; never swim across the river; stay within 10 metres of the edge, in water shallow enough to stand; and keep out of the fairway and shipping channels. Events on the tidal Thames and its foreshore need PLA consent.

Water quality

The Environment Agency assesses water quality at designated bathing water sites in England. From May to September it takes samples, and at a number of sites it issues daily pollution risk forecasts. Its bathing water quality service lists the Hampstead Heath Ladies', Men's and Mixed ponds and The Serpentine in Hyde Park as designated sites. On the data we checked, their latest annual classifications, for 2025, were: Ladies' Pond good, Men's Pond excellent, Mixed Pond excellent and the Serpentine good. Ham and Kingston, on the River Thames, was listed as a designated site from 2026 and had no classification yet. Designated sites are a small part of London's water, and not every venue in this guide is on the list. Check the service before you swim, and be wary after heavy rain.

Cold water and safety

Swim England's guidance says that in water under 15C, cold shock is more pronounced: on entry it makes you gasp, then increases your breathing and heart rate. It advises getting in slowly and taking 60 to 90 seconds to regain control of your breathing before putting your face in or swimming out of your depth. Wetsuits keep you warm, but you should still get in carefully rather than running, jumping or diving. It also recommends swimming with an organised group, club or supervised venue, telling someone your plan, keeping an eye on your buddy, and getting out if you feel too cold.

Frequently asked questions

Can I swim in the Thames in London?

Only in limited places. The Port of London Authority says most of the tidal Thames is not safe to swim and permits swimming upstream of Putney Bridge through to Teddington in west London. It lists tides, boats, cold water and sewage discharge as hazards.

Is the Serpentine open for swimming in winter?

The Serpentine Lido is closed for winter; its last public swimming day of 2026 was 24 September. The Serpentine Swimming Club swims in the lake daily between 5.30am and 9.30am.

Which Hampstead Heath ponds are open all year?

Kenwood Ladies' Pond, Highgate Men's Pond and Parliament Hill Lido are open all year. Hampstead Mixed Pond is open from April to October.

Is London's water clean enough for swimming?

The Environment Agency classifies designated bathing waters. In 2025 the Hampstead Heath Men's and Mixed ponds were excellent and the Ladies' Pond and the Serpentine were good. Check the service for the current picture.

Do I need an induction for open water swimming?

At West Reservoir, first-time swimmers need an induction. At the Royal Docks, Royal Docks' article says swimmers must become members and complete a cold water induction with the operator.

How cold is too cold?

Swim England says cold shock is more pronounced below 15C. Get in slowly, give yourself 60 to 90 seconds to control your breathing, and swim with others.

Sources

This is an independent informational guide compiled by the London BGTC Society for its members; we are not affiliated with, nor the organiser of, any club, race or venue named here. All booking and official information lives on the organisers' own websites, linked above. Dates, hours and programmes are subject to change – always confirm with the organiser before making plans.

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