A pair of fisherman got into difficulty off the coast of Little Bispham when their boat hit something in the water and began to leak.
HM Coastguard teams from Fleetwood and Lytham received a distress call to the scene at 11.20am today.
They were told that a small fishing boat was taking in water near the slip by the Fishing Club slipway.
A HM Coastguard Fleetwood spokesman said; "First on the scene was Blackpool Beach Patrol who confirmed that both fisherman were safe.
"It seems that the vessel had hit an underwater obstruction and started to take in water from below.
"The vessel immediately made its way to the shore and managed to get a rope to tie it up before it rolled over and sank."
Both fishermen were wearing life jackets and did not require medical help.
The boat was not considered a pollution risk as it had 'very little' fuel on board, and the coastguard decided to wait until low tide to recover it.