Local news outlets report the dock collapsed Saturday at The Wreck of the Richard & Charlene, a restaurant in Mount Pleasant.
Town police called a diver to ensure everyone was out of the water.
Three people were taken to hospitals with minor injuries.
Taylor Grooms tells WCSC-TV that a group was celebrating a friend's 30th birthday. They were lining the dock for a photograph when "all of the sudden we heard a loud crack."
Grooms says he and some others hung onto the side of the dock when it collapsed. He says the incident could have been worse if the creek had been at high tide.