A thief sneaked into changing rooms at Fleetwood Town FC's training ground and stole mobile phones belonging to the club's academy youngsters.
The same man is suspected of returning to the Poolfoot Farm complex in Butts Road, Thornton, on Saturday and, after finding doors locked inside, stealing between eight and 12 phones and a wallet from an unlocked outside cabin being used a changing room by a local men's side.
And Thornton Cleveleys FC, in Bourne Road, reported being burgled last Tuesday night, with till drawers stolen, as well as money from lottery machines - and even charity cash.
A spokesman said: "There appears to be people at work in [the] area targeting sports clubs, as Poolfoot and Fleetwood Rugby Club reported suspicious people hanging around.
"What makes me sick though is that our Help For Heroes collection boxes have been stolen as well.
"Lowest of the low."
Steve Curwood, the chief executive at Fleetwood Town FC, said he would "appeal to anybody with information to come forward as quickly as possible".
He said: "A theft of this nature is bad in any case but to steal from children who are trying to enjoy a game of football is very disappointing.
"The quicker the culprit is arrested the better.
"We have upped our security and everybody in the area is being vigilant to ensure this does not happen again."
Police in Fleetwood released an image, taken from CCTV cameras, of a man they want to speak to about the theft at Poolfoot Farm on Saturday. The victims traced their phones to nearby Wharfedale Avenue, a spokesman said.
The academy children's dressing room was targeted on Sunday, October 7, a club spokesman added.
Writing on social media, police said officers were also "appealing for information after a number of thefts", and added: "A suspicious male was seen in the area of the changing rooms at around 3:15pm before making off towards the Burn Naze [pub]."
A name has been given to police, it was understood, but no arrests have been made.