Arc Leisure Matlock is to close off its pool and sports hall this weekend to the public to accommodate a sporting event.
The Amateur Swimming Association (ASA) Regional Championships take place at the showpiece Derbyshire Dales District Council attraction across both Saturday and Sunday.
Each day has three sessions with 250 swimmers attending each.
Coaches, parents and spectators will take numbers up to around 2,000 people attending Arc on each day.
The eight-lane main pool at Arc has a moveable floor that meets regional competition standards. The council apologised for any inconvenience, although the fitness suite will remain open this weekend.