Senior citizens, who were entitled to swim for free at XCite in Linlithgow, will face a £1 charge for every dip from Monday (April 1).
The measure has been introduced by West Lothian Leisure, which operates as a charitable trust.
Its board say it it has no option due to “unprecedented reductions in funding.”
And it has emerged that the new charges, which apply to over 60s, will also extends to under-fives.
A spokesperson for West Lothian Leisure said: “The majority of our pay-per-visit prices have not increased since 2013 and our previous free swimming programme has had to be revised.
“We believe that this is still extremely good value.
“We also offer various payment methods including Access Xcite concessions scheme and memberships from £15 a month, which include swimming and various activities across our Xcite venues. We’ll be offering a free joining fee to registered swim users during April at our Xcite receptions.
“West Lothian Leisure is a local Community Leisure Trust and a not-for-profit charity where every penny of surplus is reinvested to improve services for the community.
“It is also one of the lowest publicly-funded trusts in Scotland.”
There has been a suggestion that the decision was sprung upon pool users but the trust said the changes were highlighted online – after being passed at a WLL board meeting on Thursday, February 28, which was open to the public.
One pool user, who did not want to be named, said: “A pound might not sound like much but you are talking about something that was completely free beforehand.
“So I think a lot of people who have been using the pool regularly will be concerned about how much this is going to cost over the year.”