Her work along the Canadian coast completed, "Acacia" returned to Boston and resumed her preparation for blockade duty along the coast of the Carolinas. When ready, she proceeded south via Hampton Roads, Virginia, and arrived off Morris Island, South Carolina on the evening of 6 January 1864. The tug served in the South Atlantic Blockading Squadron for the remainder of the war, spending most of her time near Breach Inlet in the line of Union warships outside Charleston Bar. From time to time during her deployment, she had brushes with blockade runners, occasionally forcing the escaping ships to turn back into port and compelling vessels attempting to enter back out to sea.