State Route 305 (SR 305) is a 13.50-mile-long (21.73 km) state highway in the U.S. state of Washington, primarily serving Bainbridge Island in Kitsap County and connecting it to Seattle in King County via the Seattle–Bainbridge ferry. The highway travels north through Bainbridge Island and leaves the island on the Agate Pass Bridge into the Kitsap Peninsula. SR 305 continues northwest through Poulsbo, intersecting SR 307 and ending at the SR 3 freeway. The highway was created during the 1964 highway renumbering and was preceded by Secondary State Highway 21A (SSH 21A), established in 1937. The ferry, part of the highway since 1994, is served by the Jumbo Mark-II-class MV Tacoma and MV Wenatchee and operates on a 35-minute crossing time.