Two shops in Wyre were caught selling alcohol to underage children as part of test across the borough.
Two out of 11 off-licences visited by police and council officers on Saturday night failed the test purchasing operation.
Both were given a fixed penalty notice and will be contacted "to educate them further", according to police. The shops in question have not been identified.
Police licensing officer Emma Pritchard said: "It's important for off licenses to ask for ID or even better use the Challenge 25 system which is currently in place.
"As a local policing officer I agree that these operations are a benefit to prevent a minority from causing antisocial behaviour, which could lead onto criminal offences after drinking.
"Also, a child could always become extremely vulnerable whilst drunk which is something that we do need to avoid."