Spencer Pratt and Heidi Montag were briefly detained at an airport for illegal arms possession, police in Costa Rica said.
Airport police chief Otto Arrieta said security officers found two handguns in the pair's luggage. He said the former stars of The Hills had not declared the weapons and did not have permits to have them in Costa Rica. They did not have ammunition.
Mr Arrieta said the reality TV stars were detained for questioning on Saturday, but released and allowed to leave the country the same day.
The celebrities had been in Costa Rica since August 14.