Pran Buri Forest Park is the town's most rewarding sight. A raised wooden boardwalk loops through mangroves beside the Pran Buri River estuary, with lookouts over the channels and mudflats. It is small enough to visit in an hour, but go slowly: mudskippers, fiddler crabs, herons, and kingfishers are easier to spot when you stop moving.
The park also has a pine-fringed beach side and boat trips through the estuary when water levels and operators line up. It makes a good morning outing before the heat builds, especially if you are continuing south toward Prachuap Khiri Khan.