Hydromaniacs seeking one last seafaring adventure before the autumn chill sets in can head out with H2O Hospitality, a new charter company running three-hour clamming tours in the Peconic Bay ($100 per person for two people, $90 per person for three to six; 631-553-0293; h2ospitality.com). Trips begin in Greenport (2.5 hours from midtown via the Jitney), where you’ll climb aboard Captain Libby Koch’s 27-foot powerboat. Koch hands out clam rakes, then you go to town prodding the shallow seabed for quahogs both large (chowder clams) and small (littlenecks); when your arms tire, hop back on the boat for a BYO or boxed-lunch picnic ($20). Clammers typically harvest a dozen bivalves apiece, and Koch supplies ice and bags for toting your harvest home. Outings may be scheduled for any day of the week through mid-October; departure times depend on the tidal schedule.