Visitors to swimming pools and sports centres were being warned this week to secure their belongings after a theft at Seaford Head Swimming Pool.
Sussex Police said a Nokia Lumina 520 mobile phone in a black leather case, a debit card and £30 in cash were stolen from an insecure locker.
They are appealing for anyone with information to come forward.
The items were taken from the men’s changing room at the pool in Sutton Avenue between noon and 1.15pm on Thursday February 20.
Sergeant Stuart Mullins said: “Our advice when visiting any sports centre or swimming pool would always be to secure all of your valuables in a locker.
“But if that is inconvenient it would be better to leave them at home.
“Never leave any items insecure in any of your clothes or bag. Anyone with information about this theft is asked to contact police on 101 or firstname.lastname@example.org.”