The three men from Gavle, in central Sweden, had stopped by a local swimming pool for a dip. When they returned to the pool locker room, they discovered that someone had made off with their uniforms, their commander, Thomas Fahlstedt, said Thursday.
"Everything was gone except for the underpants and the shoes," Fahlstedt said. "They had to drive back in the fire engine wearing only those."
Fire officials reported Wednesday's theft to police, who promptly sent two officers - both female - to investigate.
Swedish news organizations reported the two officers were amused by the firemen's predicament. But they took the report seriously, arresting a man with a bag full of firefighters' gear, and returning the gear to the station.
The motive for the theft was not known.
"People stared a bit," one of the firefighters, Posa Serenius, was quoted by the Expressen newspaper as saying. "But I guess it went well."
