If you are traveling from points north (Boston, Rhode Island, Cape Cod etc.) you can take the Cross Sound Ferry from New London, Connecticut to Orient Point, Long Island. Call 631.323.2525 to make your reservation, early. From Orient Point it is a 30 minute drive to Greenport to the North Ferry Terminal to Shelter Island. From Bridgeport, Connecticut to Port Jefferson, New York, you may take the Bridgeport - Port Jefferson Ferry. You may make a reservation at 888.443.3779 or 631.473.0286.  Port Jefferson, NY is about an one hour drive to Greenport, NY, or to North Haven, NY to transfer to a Shelter Island Ferry.