SC 703 begins at a partial interchange with U.S. Route 17 (US 17; Johnnie Dodds Boulevard) in Mount Pleasant, within Charleston County.

This interchange is on the eastern end of the Arthur Ravenel Jr. Bridge and just south of the Mount Pleasant Memorial Waterfront Park.

It travels to the southeast and has an intersection with Patriots Point Road and Magrath Darby Boulevard.

It passes Christ Our King-Stella Maris School at the eastern terminus of Interstate 526 Business (I-526 Bus.

It crosses over the Intracoastal Waterway on the Ben Sawyer Bridge and enters Sullivan's Island.