Media outlets report that city council voted 7-5 on Tuesday to oppose both drilling and seismic testing to survey for oil. Charleston is now the 20th community in the Carolinas - and the largest in South Carolina - opposing drilling.
Myrtle Beach, the heart of South Carolina's $18 billion tourism industry, considers a similar resolution next month.
The federal Bureau of Ocean Energy Management is taking comment through the end of the month on what should be studied in an environmental impact statement on Atlantic drilling.
Opponents of drilling worry that spills could damage fisheries and the important coastal tourism industry. Supporters say drilling can be done safely and will bring jobs and revenues to the Carolinas.