Sullivan's Island Beach is located near Charleston, across the harbor on Sullivan's Island. You take the gorgeous Arthur Ravenel Jr. Bridge to get across the harbor from Charleston and then drive past salt marshes to get to Sullivan's Island and the beaches. 

Sullivan's Island Beach is the most rugged of the beaches on the island. Isle of Palms is a little more developed. There is a hideously ugly lighthouse at Sullivan's Island Beach and some attractive homes with tropical landscaping. A low boardwalk takes you out to the sand, and from the boardwalk the beach looks the prettiest, with the dunes and sea oats in full view, plus some cute yellow wildflowers. Once you reach the sand, the beach is pretty plain. It is a wide expanse of mucky stained sand. I don't know what stains it- it looks like oil but probably is something else. When we were there, a howling wind was making interesting patterns in the sand. 
Continue along the island to Isle of Palms Beach, which has an adorable main strip where you can get an ice cream at Ben and Jerry's. You will pass Breach Inlet where you can enjoy fantastic views from Thompson Park.
After, eat at Saltwater Cowboys (a 12 minute drive from Sullivan's Island Beach), enjoying its gorgeous three levels, all with super views.
On your way back to Charleston town, stop below the Arthur Ravenel Jr. Bridge at Mt. Pleasant Pier.

Directions

Sullivan's Island Beach is located at 1851 Thee St, Sullivan's Island, SC 29482. You can park along the road in the neighborhood.

Click on map for interactive view