Parliament Hill Lido is an unheated outdoor pool and it opens 365 days a year. Finchley Lido is also an unheated outdoor pool, and its operator says it opens when the temperature is above 22°C.
Two unheated lidos, the same city, and between them the entire range of what outdoor swimming in London means. One is a year round discipline. The other is a warm afternoon that may not arrive.
The word lido tells you nothing useful. Heated or unheated does, and so does the season, and the operators publish both if you go and look. Here is where each one sits.
The heated ones, open all year
These are the pools you can use in February. All four are operated by Better, which labels the temperature and the season on each.
London Fields Lido, Hackney. Heated, 50 metres, open all year round. Olympic length, lane swimming and lessons, with a café and a large sundeck.
Charlton Lido, south London. Heated, 50 metres, open twelve months a year. The Olympic sized pool comes attached to a gym, studio, tennis courts and a café, which is why it calls itself a lifestyle club rather than a lido.
Pools on the Park, Richmond. Heated, 33 metres, open all year, and the only one that publishes a number: maintained at 25°C. It is floodlit after dark, so you can swim outdoors in the evening in winter, which is a rarer thing than it sounds.
Oasis Sports Centre. Heated, 27.5 metres. The building started life as a Turkish bath in 1728, which makes it older than almost everything else in this piece by about two centuries.
The unheated ones, and their very different seasons
Parliament Hill Lido, Hampstead Heath. Unheated, 60 metres, chlorinated, open 365 days a year including bank holidays. Longer hours in summer, shorter in winter, and the summer day is divided into sessions: some bookable, some drop-in.
Tooting Bec Lido. Unheated, 91 metres, and its operator calls it the UK’s largest freshwater outdoor pool. It is seasonal: rechecked on 28 September 2026, the centre was marked as not currently open, and the only reopening notice on its page was the one for Friday 1 May, which was this year’s, so next year’s date is not yet published.
Hillingdon Lido. Unheated, 50 metres, Grade II listed, open April to October. There are cascade fountains and, usefully for families, a heated splash pool for children even though the main pool is not.
Finchley Lido, Barnet. Unheated, 25 metres, summer only, and open when the temperature is above 22°C. A published weather condition on a swimming pool is unusual enough to plan around. There is an indoor pool on the same site for the days it does not open.
The Serpentine Lido in Hyde Park is the other one worth knowing: a marked 100 metre stretch of the lake, open to the public at weekends from mid May and then daily from June to mid September, in sessions from 10am to 1.30pm and 2.30pm to 6pm. Members of the Serpentine Swimming Club, the oldest swimming club in Britain, swim there every morning of the year until 9.30am, from 5am by the Royal Parks’ own Hyde Park FAQ or 5.30am by its swimming page, and in the race on Christmas Day, which is why you see people in the water in January.
The rules at Parliament Hill, which are the strictest published
It is open every day, so the rules do more work than elsewhere.
Under 16s and over 60s swim free before 9:30am, on production of proof of age. That is the single most valuable line on the whole page and almost nobody repeats it.
The Hampstead Heath swimming facilities now take cashless payments only. That took effect on 1 October 2026, so a kiosk that took coins last month does not take them now. Bring a card.
One adult may supervise a maximum of four under 16s, and no more than two of those may be under 8. Children under 8 need an adult in the water with them, not beside the pool.
Evening sessions are adults only, 18 and over, lane swimming, and there are none on a Tuesday, Saturday or Sunday. No children, and photo identification may be requested.
It stays open in all weather except very high winds and thunderstorms. If swimming is suspended briefly they move people between booked slots and drop-in sessions, and they do not refund lost swimming time unless the lido closes completely.
Drop-in sessions reach capacity fast. When they do, staff may run one in one out, break the session, pause admission or close it early.
The sauna is open in winter and shut in summer
This is the detail that tells you what Parliament Hill actually is.
The lido sauna opens for the winter season and closes for the summer, which is the opposite of how most people imagine a lido works. In an unheated pool in January, a sauna is not a luxury.
Sauna tickets cost extra and cannot be bought without a swimming ticket. They can only be bought in person, by the person using it, and cannot be bought for somebody else or booked in advance. Adults only.
Two pools, two superlatives
Worth knowing if you like a tidy answer and are not going to get one.
Places Leisure describes Tooting Bec as the UK’s largest freshwater outdoor pool, at 91 metres.
Better describes Jesus Green in Cambridge as the longest pool in the UK, at just under 100 metres, giving its length as 91.4 metres.
Both claims can hold at once, because one is about length and the other about volume of water, and the two pools are within half a metre of each other in length. But if you have read that a particular lido is the biggest in Britain, that is why you have also read it about a different one.
What to know
Heated or unheated is the only question that matters. Four London lidos are heated and open all year. The rest are a seasonal proposition or a cold water discipline.
Parliament Hill is open every day of the year. Unheated, 60 metres, and with a sauna that runs in winter only.
Swim free before 9:30am at Parliament Hill if you are under 16 or over 60. Take proof of age.
Tooting Bec is shut until the spring. Its 2027 reopening date is not yet published, so check before travelling between October and April.
Finchley needs 22 degrees. Do not plan a trip there around a forecast you have not read.
Book where booking exists, and read the refund line. Tooting Bec states plainly that bookings are non-refundable, and Parliament Hill does not refund weather interruptions short of a full closure.
Everything here was taken from each operator’s own published pages and rechecked on 28 September 2026. Where two operators make competing claims both are given rather than one being quietly chosen. Seasons, temperatures and prices change every year, so confirm before you travel.
Every lido, in detail
Each of these now has its own page, because the prices, hours and rules differ far more than they look.
Parliament Hill Lido is 60 metres, open all year, and charges £5.00 at breakfast against £8.80 at midday in summer.
The Hampstead Heath ponds are £5.00 flat all year, and the Men’s Pond runs a degree or two warmer than the Mixed.
London Fields Lido is heated to 24°C year-round at £6.40, and its adult walk-up price is identical at peak and off peak.
Charlton Lido charges £11.50, nearly double London Fields, but a one-hour sauna booking includes the pool.
Tooting Bec Lido is 91.4 metres, the largest freshwater pool in the UK, and shut from 1 October to 30 April.
Brockwell Lido bars junior swimmers whenever the water drops below 15°C, and its hours are republished every week.
The Serpentine Lido is the cheapest of all at £2.50 after 4pm, and the most central, but closed for winter.
Where to go next
Hyde Park covers the Serpentine Lido in detail, including the swimming club that has the water before the public every morning, and the rest of the park’s published rules.
The best parks in London and Richmond Park cover the green space these pools sit inside, and Richmond is where the heated year round pool is.
Spa days and private spas are the indoor version of the same afternoon, with the hotel policies to check first.
Free things to do in London covers the rest of what costs nothing, and things to do at the weekend cover the days these places fill up.
Padel is the other sport Londoners have taken up in numbers, and it has the opposite pricing problem to the lidos: the pools publish everything and the padel clubs publish no court price at all.
Questions we get asked
Which London lidos are open all year?
Four heated ones and one unheated one. London Fields in Hackney, Charlton, Pools on the Park in Richmond and the Oasis Sports Centre are all heated and open year round, with Pools on the Park maintained at 25°C and floodlit after dark. Parliament Hill Lido on Hampstead Heath is open 365 days a year including bank holidays but is unheated, at 60 metres and chlorinated.
Are London lidos heated?
Some are and some are not, and the operators say which. London Fields, Charlton, Pools on the Park and Oasis are heated. Parliament Hill, Tooting Bec, Hillingdon and Finchley are unheated. Only Pools on the Park publishes a target temperature, at 25°C. Parliament Hill and Tooting Bec both display live water temperatures at the pool and online, which is worth checking in advance.
When does Tooting Bec Lido open?
It runs a spring and summer season, which opened on Friday 1 May this year, and next year’s date is not yet published. Rechecked on 28 September 2026, its facilities were marked as not currently open. It is unheated and 91 metres long, described by its operator, Places Leisure acting as agent for Wandsworth Council, as the UK’s largest freshwater outdoor pool. Bookings there are non-refundable.
Can you swim free at a London lido?
At Parliament Hill Lido, under 16s and over 60s swim free of charge before 9:30am on production of proof of age. That is published on the City of London’s own page for the lido and is the clearest free swimming concession in London. Note that since 1 October 2026 the Hampstead Heath swimming facilities have taken cashless payments only, so bring a card.
What is the biggest lido in London?
Tooting Bec at 91 metres, which its operator calls the UK’s largest freshwater outdoor pool. Parliament Hill is 60 metres and London Fields and Charlton are both 50. For comparison, Better describes Jesus Green in Cambridge as the longest pool in the UK at 91.4 metres, so the two claims sit within half a metre of each other and describe different things, one length and one volume.
Is there a sauna at a London lido?
Parliament Hill Lido has one, and it runs in the winter season and closes for the summer, which surprises people. Sauna tickets are sold in addition to a swimming ticket and cannot be bought without one. They must be bought in person by the person using the sauna, cannot be purchased for anybody else, cannot be booked in advance, and are for adults aged 18 and over.
Written by Robert J Wills, no. 149 in the guide.
Last checked 28 September 2026 against the venues' own published information. Nobody pays to appear here and we take no bookings.
