Councillors have voted in favour of a draft plan to sell the former Edgeware pool site and put money into a community centre instead.
The St Alban's Swim Club says it will reoccupy the site on Monday because the land should be used for community purposes.
Spokesperson Kevin McDonald says members will go in to repaint and rebuild the old clubroom, even though the council owns the land.
"I'm not sure about the legality of it, but we know that we own the clubroom and we're going back in there to reoccupy it."
He says his group will present a submission against the Council's move to sell the land for housing development.
