The Brewster Fish House, on Main Street (Route 6A) is arguably the best seafood restaurant in town. It's small, but the service is always great! They may not have a traditional boiled/steamed lobster on the menu at all times, but last summer I had a butter-poached lobster that was INCREDIBLE! Fish chowder is also a MUST.
Brewster Fish House
2208 Main, Brewster, MA 02631