Operators of outdoor swimming pools have criticised the timing of the government announcement allowing them to reopen.
Some have decided not to open, claiming a lack of preparation time has made a shorter summer season “unviable”.
Many are run by community groups or charities and have mounted fundraising efforts in order to survive.
The government said “comprehensive guidance” was available to leisure operators.
As part of the easing of coronavirus lockdown restrictions, swimmers can visit outdoor pools from Saturday, while indoor gyms, pools and sports facilities can reopen from 25 July.
Pool operators have said the announcement came too late to allow them to go through the process of cleaning and filling pools and meeting both water-quality and coronavirus safety standards.
There are more than 100 outdoor public swimming baths around the country – many restored and run by community groups.
The volunteer-run Hilsea Lido in Hampshire said on Facebook, “with a heavy heart”, it would not reopen until 2021.
“With no clear indication of when we would be allowed to open, we were not able to prepare the pool in advance.
“Hilsea Lido is a massive pool and the preparation costs reflect this,” it said.
Shap Lido in Cumbria – England’s “highest heated pool” – said it would “not be financially viable” to open for a six-week summer period, as did Portishead’s community lido in Somerset.
In Berkshire Covid-19 restrictions meant contactors were not been able to complete repair work on Northcroft Lido, which will remain closed as a result.
Peterborough’s 1930s art deco lido will also not reopen this weekend after its operator was forced to hand back its council contract due to financial difficulties during the crisis.
Among those planning to open is Lymington Sea Water Baths in Hampshire which dates back to the early 19th Century.
Manager Hugo Ambrose said: “It’s certainly not going to be a good, viable year but I do think there’s a community we need to work with.”
Cornwall’s coastal art deco Jubilee Pool in Penzance is hoping to reopen at the end of July.
Operations officer Nicola Murdoch said reopening “isn’t possible at 48 hours notice” and would require a deep clean, staff training and social distancing measures.
“It’s fantastic to have the green light, but a little more notice like indoor leisure centres would have been helpful,” she added.
Droitwich Lido plans to open in August thanks to a £55,000 grant from Wychavon Council.
Manager Tim Kirkham said: “We’re in winter mode – we’ve got a lot of work and power washing to do but I’m sure we can do it. People have been so supportive.”
However its usual capacity of 550 swimmers will be reduced to about 100.
In London, the 1930s Parliament Hill Lido has introduced online booking for hour-long socially distanced sessions for an “adjustment to a new way of swimming”.
The Department of Media, Culture and Sport said: “We recognise the importance of reopening our indoor and outdoor pools as swimming is a great way for people of all ages to stay fit and healthy.
“We have published comprehensive guidance to enable the reopening of outdoor pools and outdoor water parks.”