Volunteers have been left heart broken after thieves stole money from the cafe and office at Bourne Outdoor Swimming Pool last week.
The thieves broke into the cafe after it had shut on Thursday, stealing money before smashing through to the office at the pool off Coggles Causeway.
The pool, which is a charitable company run by volunteers and relies on donations to stay open, has been left with a loss of about £500 in the money taken and cost of repairs to two broken doors.
Bourne Outdoor Swimming Pool management committee chairman Mandy Delaine-Smith: “I am very disappointed that someone would do something like this.
“It is heart-breaking, and it was on my daughter’s birthday as well.
“It causes hurt for all the volunteers who work so hard to keep this facility open for the community.
Mrs Delaine-Smith said it was the pool’s policy not to keep cash on the premises at night and it was a fluke that there was a small amount there on that occasion.
She said: “It is money we can’t afford to lose, even after a reasonably good season.
The cafe, on the Abbey Lawn, opened again late on Friday after checks by police and crime scene investigators.
Police are linking the incident to vandalism at nearby Bourne Town Football Club, last month.
Police sector inspector Mike Burnett said: “These organisations run sport for local people to participate in as well as running teams. They are volunteers at both the pool and the football club.
“I would appeal to the offenders who have committed these crimes to think about the long-term impact they are having on groups of volunteers who are trying to get all people swimming or playing football.
“It is particularly damning on whoever is doing it. A small minority are having a big impact.
“I am determined to bring these people to justice.
“We will be stepping up patrols.”
Police are appealing for anyone who saw anything suspicious in the area on Thursday night to call them on 101 quoting incident 131 of August 16.