Police were called around 8.05pm yesterday (Monday, April 12) to a report of a disturbance in The Esplanade.
It was reported men had been fighting with weapons, including bats and machetes, in The Esplanade car park.
Officers attended the scene with the groups making off in two vehicles.
Detectives are appealing for information and urging anyone who witnessed the disorder, or has video footage of the incident, to come forward.
Det Insp Abi Finch-Hall, of Blackpool Police, said: “An investigation is underway following serious disorder in Fleetwood.
“We will not tolerate such behaviour and enquiries are ongoing to identify suspects and to make further arrests.
“Resources have been increased in the area and you should expect to see a substantial police presence as we target the individuals we believe to be involved.
“Incidents of this nature are rare and we understand this will have caused some concern in parts of the community.
“I would urge anyone with information about this disorder to come forward. Do you know who was involved? Please contact us if you can help.
“I would also urge anyone who might have CCTV or camera footage showing the fighting to speak to police.”
Anyone with information can call 101 or email firstname.lastname@example.org quoting log 1539 of April 12.