Portavadie, Argyll

Set beside Loch Fyne on Scotland’s west coast, Portavadie was first planned as an oil-rig construction site, though the project never came to fruition. It has since become a marina resort with self-catering accommodation, a restaurant and bar, a small shop, and an extensive leisure complex. Its standout feature is thought to be Scotland’s largest heated outdoor infinity pool, looking across the water towards the Isle of Arran. Guests can also use outdoor spa pools, a sauna, indoor pool and gym, while massages and facials can be booked separately. A woodchip biomass system supplies much of the site’s energy. £14 for a 90-minute swim, sauna and hot tub

Beccles Lido, Suffolk

People have swum in the River Waveney for generations, and Beccles gained an enclosed bathing area carved from the river in 1894. The market town, on the southern fringe of the Broads, later replaced it with an unheated riverside pool in 1959. Half a century on, the site developed into a lido with three pools. For the first time, the water is being heated to 28C through winter, initially until 3 January and potentially until the end of March if demand is strong. The main 30-metre pool has a diving board and slide, alongside splash and toddler pools, a wood-fired sauna and cafe. Planned sessions include lane swimming, family swims and aquacise. From £7.40 adults

Hathersage Swimming Pool, Derbyshire

The Peak District village of Hathersage marked 90 years of its 30-metre outdoor pool in July. It was donated to local residents by philanthropist George Lawrence, who later died during the Sheffield Blitz. The old coke-fired boiler, once capable of warming the pool to only 20C, has been replaced by a renewable heating system, with water recently reaching 27C. The pool opens every day of the year, though with shorter hours between November and March. There are warm showers beside the pool and a sauna from October, as well as evening swims with live music and a cafe offering hot drinks and homemade dishes. £8 adults

Thames Lido, Reading, Berkshire

Reading’s pool at King’s Meadow opened in 1902, originally supplied by the Thames and reserved for women. It moved to mains water during the 1950s, shut in the 1970s, and eventually returned following a three-year restoration completed in 2017. The 25-metre outdoor pool is kept between 20C and 24C throughout the year. Facilities include a 38-40C hot tub, sauna, steam room, cold-water drench bucket and a shower designed like a ship’s funnel. Massage appointments are also available. The smart waterside restaurant starts serving breakfast at 9am, with options such as granola, bacon rolls and Turkish-style eggs, followed by lunch and dinner. From £25 for a two-hour swim, sauna, steam and hot tub

Chesham Moor, Buckinghamshire

The swimming pool at Chesham Moor is said to have begun life as a deep puddle where people bathed during the 1890s. It is now a 25-metre, spring-fed lido, modernised in 2023 with a Nasa-developed ionisation system that reduces the need for chlorine. Solar panels help run the site, and the water is generally maintained at 27C all year, although extreme cold can lower the temperature slightly. Daily sessions combine lane swimming and general use, with aqua fitness classes and swimming masterclasses also on offer. Visitors can make use of outdoor circuit sessions, tennis courts and riverside walks nearby, then stop at the cafe for coffee, sausage rolls, sandwiches or cake. From £7 adults

Sea Lanes, Brighton, East Sussex

Sea Lanes opened in 2023 as a link between traditional pool swimming and the open sea. Its beachfront facility has a 50-metre pool with six lanes, heated to at least 19C all year. Coaching caters for everyone from complete beginners to sea swimmers and triathletes. Nearby food and drink options include brunch and coffee, fire-cooked lunches and dinners, and a bar serving draught beer, wine and cocktails. Four miles along the promenade stands Saltdean Lido, a 40-metre crescent-shaped modernist pool dating from 1938. It opens for December only during winter, when the water is heated to 19C, and a separately run sauna is also available. £11.90 adults

Hampton Pool, London

Built in 1922 beside Bushy Park in south-west London, Hampton Pool is now operated by a charity and welcomes swimmers every day of the year. Its 36-metre outdoor pool is heated to a balmy 28C, with a separate 12.5-metre learner pool also available. The site includes a gym, exercise classes and the Sundeck Cafe, serving simple warming meals such as porridge, soup and jacket potatoes. Special events include moonlight sessions and festive swims. There are plenty of other heated outdoor pools around London, including London Fields Lido, Oasis Sports Centre, Charlton Lido, Pools on the Park in Richmond and Park Road Lido in Crouch End.

Lido Ponty, Rhondda Cynon Taf

Pontypridd’s National Lido of Wales first opened in 1927 and has welcomed generations of swimmers, including a young Tom Jones. After a major restoration, it reopened in 2015 with three heated pools: a main pool, activity pool and splash pool. During summer, the water is kept at 28C, but the temperature drops to a brisk 14-15C in winter. Weekend cold-water sessions run from 24 October to 28 November and are open to swimmers aged 16 and above. Hot showers are available both indoors and outdoors, along with heated changing areas. Those seeking warmer water can wait for the Boxing Day and New Year’s Day sessions, when the pools return to 28C. £4 adults

Bristol Lido

This Victorian open-air pool began welcoming swimmers in 1850, before closing in 1990 and narrowly avoiding conversion into apartments. It was instead purchased and revived by businessman Arne Ringner, who later acquired Thames Lido, and reopened in 2008. The 24-metre pool stays between 20C and 24C throughout the year. Visitors can combine a swim with the sauna, steam room and hot tub, while the poolside restaurant and bar hosts regular supper clubs. Seasonal events include synchronised swimming performances, Christmas meals and a New Year’s Eve celebration with a two-hour swim followed by a five-course dinner. From £25 for a two-hour session – swim, sauna, steam and hot tub

Faversham Pools, Kent

Faversham Pools has three heated outdoor pools: a 33-metre lido with 1, 3 and 5-metre diving boards, a rapid-water fun pool, and a toddler pool with slides. There is also a 25-metre indoor pool and whirlpool bath. The two smaller outdoor pools operate from April to September, while the lido stays open year-round with reduced hours from September to April. Winter outdoor slots take place on Tuesday and Thursday evenings and Sunday mornings, and are lane-swimming sessions for over-16s only. Tides Cafe provides filling homemade food for colder days, including soups, toasties, macaroni cheese and curries. £8.50 adults