The lido boom and bust

On 31 May 1935, Penzance opened a triangular sea-water pool on Battery Rocks, below the town, as part of the celebrations for George V's Silver Jubilee. By August, Wikipedia records, almost 60,000 people had been through the turnstiles. Jubilee Pool is still there. It was closed in 1992, reopened in 1994, wrecked by storms in 2014, reopened again in 2016 and is now heated from a geothermal well. Its story is the story of the British lido in miniature: a boom, a long decline, and a stubborn comeback.

Wikipedia's history of lidos in the United Kingdom says that 169 were built in the 1930s, that hundreds have closed since, and that 127 remain open in England. Those are big claims from secondary sources, and there is no open national list that lets anyone check them. So I made one: a register of 73 lidos and open-air pools whose dates or fate I could document from open sources, plus every working open-air pool, lido and tidal pool that OpenStreetMap's mappers have tagged.

It is not a census. It is a careful sample, and its biases (famous pools and survivors are far better documented than the ones that quietly closed) are spelled out below. But it is enough to see the shape: a boom concentrated in a single decade, a bust concentrated in three, and a revival that is almost entirely a twenty-first century story.

01 · The mapEvery lido I could document

Each dot is a lido or open-air pool. Drag the slider to watch them open and close: a pool appears in the year it opened (or the middle of its decade, if only the decade is known), turns coral while it is shut, and turns gold if it reopened. At 2026 the map adds the working open-air pools that are in OpenStreetMap but not in my register (small dots). Tap a dot for its dates and the source, or search for a place.

02 · The boomOne decade built most of them

Outdoor bathing places are much older than the word lido. The oldest pool in the register, Cleveland Pools in Bath, was built in 1815; Clifton's Victoria Baths in Bristol opened in 1850; Tooting's bathing lake in 1906. The word itself, Italian for a beach, probably came into English through "Lansbury's Lido", the newspapers' nickname for the Serpentine bathing place in Hyde Park after it was revamped in 1930 and opened to mixed bathing.

Then came the boom. Of the 49 pools in the register whose opening year or decade I could document, 33 (67%) opened in the 1930s, against 6 in the 1920s and 4 after 1945. Nine opened in 1935 alone, the year of George V's Silver Jubilee, among them Jubilee Pool, Tinside in Plymouth, Hilsea in Portsmouth, Sandford Parks in Cheltenham and Uxbridge. London County Council alone built 13 lidos between 1920 and 1939, according to the Parliament Hill Lido article.

These were civic showpieces. New Brighton's pool, opened in 1934, was the largest lido in Britain when it was built and cost £90,000. Saltdean, with its curved wings and sun deck, was, says its Wikipedia article, hailed as the most innovative design of its type in Britain. On 11 July 1971, Finchley Lido took 11,962 visitors in a day, still described as the record for a UK lido. Two of them, Finchley and Aldershot, were venues for the 1948 London Olympics.

In the open record, one decade accounts for 67% of all the lido openings anyone has dated.

03 · The bustThree decades of closures

The register has a closing year or decade for 24 pools. 19 of them (79%) closed between 1970 and 1999: 5 in the 1970s, 6 in the 1980s and 8 in the 1990s, the worst decade. The pools that closed had typically been open for 61 years (median, 17 pools with both dates). Wikipedia's history blames cheaper foreign holidays; the individual articles add council cost-cutting, ageing equipment, neglect and the weather. Cleethorpes' bathing pool was wrecked by storms in January 1978, and New Brighton's in 1990.

Among the documented pools, the number open peaked at 37 in 1962 and fell to a low of 22 in 2002, when 17 stood closed. Because the register leans towards pools famous enough to have an article, and survivors are far more likely to be famous, this curve certainly understates the fall. Wikipedia's figures imply that the real decline was much steeper: 169 built in the 1930s alone, and "hundreds" closed since.

04 · The comebackCampaigns that won

Here the register tells a story that the national totals hide. Of the 33 pools of known fate that closed at some point, 14 (42%) have reopened, and 12 of those reopenings came after 2000. The typical comeback took 7 years (median of 11 with both dates). The longest wait was Reading's Thames Lido, a 1903 Edwardian ladies' pool that closed in 1974 and reopened 43 years later, in 2017.

Most of these comebacks followed a local campaign: the Brockwell Lido Users, Save a Lido Today in Droitwich, the Jubilee Pool Association, the Saltdean Lido community interest company, the trust that took over Portishead. Several are now run by charities, community companies or shareholders rather than councils: Jubilee Pool, for example, is owned by about 1,400 local shareholders. Brockwell Lido shows how fragile it can still be: its operator went into administration in April 2026 and the council took it back.

Of the 33 documented 1930s lidos, 27 have a known fate: 17 are open today (9 with no long closure on record, 8 after a comeback) and 10 are closed. The register holds only about 20% of the 169 that Wikipedia says were built in that decade, and the missing ones are likely to be mostly the ones nobody wrote about, which is to say mostly the closed ones.

05 · TodayWhere you can still swim outdoors

Combining the register with OpenStreetMap, I can place 82 working open-air pools, lidos and tidal pools in the UK: 71 in England, against the 127 that Wikipedia says remain open in England. So the map is a floor, not a count: mappers have not tagged every outdoor pool, and I only kept features whose name or tags say open-air, lido, outdoor or tidal. The pattern is still clear. 49 of the 82 (60%) are in London, the South East and the South West, and 44% are within 2 km of the sea.

The South West leads by a distance, with 24 pools, or 4.2 per million people, and 19 of them are within 2 km of the sea. OpenStreetMap tags 12 working tidal and sea pools, basins on the shore that the sea refills, and 6 of them are in Cornwall: Bude, Chapel Rock at Perranporth, Millendreath, Porthtowan, Treyarnon and Trevone. Add Jubilee Pool, Tinside, Shoalstone at Brixham, Devil's Point in Plymouth and the Rock Pool at Westward Ho!, and the coast of Devon and Cornwall holds the biggest cluster of outdoor swimming on my map. The North, by contrast, has 7 working pools on my map across three regions; Grange Lido, described in a 2011 Guardian report quoted by Wikipedia as the last remaining lido in the north of England after those at Blackpool, Scarborough and Morecambe were demolished and filled in, closed in 1993 and is being repaired as a public space, not a pool.

London is the other cluster. The register has 17 London entries, 11 of them opened in the 1930s, more than any other region. Today I can place 9 working London lidos, among them Tooting Bec (100 by 33 yards, the largest pool in England), Parliament Hill, Brockwell, London Fields, Charlton, Hampton and the Serpentine. Victoria Park and Peckham Rye are among those that closed and were demolished.

06 · LimitsWhat this can and cannot show

This is a documented sample, not a census. The register holds 73 entries; 58 draw on Wikipedia text, the rest on Wikidata items or OpenStreetMap tags. There is no open national list of lidos with dates. The best-known compilations (Janet Smith's Liquid Assets for English Heritage, and enthusiasts' lists online) are not open data, and I did not copy them.

Survivors are over-represented. A pool that is open, listed or the subject of a campaign is far more likely to have a Wikipedia article, a Wikidata item or detailed OpenStreetMap tags than one demolished in 1975. That makes the closures and the decline look smaller than they were, and the comebacks look more common. The timing patterns (when pools opened, when they closed) are more trustworthy than the shares.

Dates are as the sources give them. Where articles disagree (Black Rock in Brighton was demolished in 1978 according to one article and 1979 according to another) I note it. "Closed" means the closure after which a pool stood empty longest; several pools have closed more than once. 14 entries have an unknown status today.

OpenStreetMap shows mappers, not pools. I kept 112 sites named or tagged as open-air pools, lidos or tidal pools; 74 are tagged as working pools, 10 as disused and 28 are named but not tagged clearly enough to tell. Wikidata knows 83 UK items in lido and swimming pool classes, but only 9 have an opening date.