SR 307 begins at an intersection with US 17/SR 25 in Garden City. The route heads northwest along Dean Forest Road, before making a sharp turn to the northeast to its interchange with Interstate 16. It heads on a more northeastern direction before it curves to the northwest, and then to the north. Before skirting the southeastern part of the Savannah/Hilton Head International Airport, it intersects US 80/SR 26, and then curves to the northeast along Bourne Avenue. Heading due east, SR 307 intersects SR 21. Here, it begins a concurrency with SR 21 Alternate. The roadway curves to the southeast, where SR 21 Alt. splits off, and makes a northeasterly jaunt until it meets its northern terminus, an intersection with SR 25 just north of Garden City.