SR 3 was established during the 1964 highway renumbering and codified in 1970 as the successor to Secondary State Highway 14 (SSH 14) from Shelton to Belfair, Primary State Highway 14 (PSH 14) from Belfair to Gorst, and PSH 21 from Gorst to the Hood Canal Bridge. PSH 21 was previously part of State Road 21 from 1915 to 1937, while PSH 14 was part of State Road 14 and the Navy Yard Highway from 1919 to 1937. The present SR 3 freeway was opened in 1968 in the Bremerton area and was extended north to Poulsbo in 1973 and to Bangor in 1977.