The ban is on Cleveleys and Fleetwood beaches between May and October
Wyre council are bringing in a ban from 1 May - 30 September.
The ban will be enforced on Fleetwood beach from the east side, of the slipway opposite to the end of Promenade Road eastwards to the west side of the site of the former Fleetwood pier and on Cleveleys Beach from Cafe Cove to Wyre borough boundary.
They say it's in an effort to prevent contamination to the bathing water, thanks to mess dogs may leave behind.
A spokesperson for the council said:
"It's not acceptable to not pick up after your dog on the beach.
The sea washing it away is not an excuse, as it will contaminate the bathing water quality.
Please always pick up and remember any bin will do."
Anyone exercising their dog on these prohibited parts of the beach are advised they will be issued a fixed penalty notice.
The council say The majority of the coastline with public access is accessible to dogs.