SR 512 begins at a partial cloverleaf interchange with I-5 in Lakewood, a suburb of Tacoma in the Seattle metropolitan area. The interchange only uses three cloverleaf ramps, with turns from southbound I-5 to eastbound SR 512 accessed via a traffic signal; beyond the interchange, the highway continues west to an intersection with South Tacoma Way. The six-lane freeway travels southeast along the north side of Joint Base Lewis-McChord and through an interchange with Steele Street before entering the suburban community of Parkland. SR 512 then intersects Pacific Avenue, carrying a section of SR 7, in a partial cloverleaf interchange located near the Pacific Lutheran University campus.