Equal parts ’70s time capsule and breezy beach vibe, this island addition offers nostalgic maritime decor, as well as throwback menu items, from baked oysters to fried seafood baskets. However, circa-2023 culinary flourishes, like the miso brown butter that dresses a warm lobster roll and bright, fresh crudos, up the ante for fish camp fare. (No fancy upgrade needed for the stellar smoked fish dip.) Fruity, frozen cocktails and Westbrook’s Crab Claw, a crushable lager made exclusively for Sullivan’s, wash it all down.