Interstate H-3 is a highway in the American state of Hawaii. It begins at the Halawa Interchange with Interstates H-1 and H-201. The highway then runs along a viaduct through Halawa Valley for about 6 miles. It then goes through the Tetsuo Harano Tunnels through the Koolau Mountains. Once on the eastern end of the tunnel, the highway follows a viaduct built along the side of Haiku Valley until the Kaneohe Interchange with state route 63 (Likelike Highway) which leads into the town of Kaneohe. The highway then continues to the Halekou Interchange with state route 83 (Kamehameha Highway). Four miles farther, it reaches the main gate of Marine Corps Base Hawaii. The route is 15.32 miles (24.66 km) long.