Helena was present at Pearl Harbor on the morning of 7 Dec 1941. The ship was torpedoed, but not sunk. Helena was repaired and put back into service.
The Helena, along with other U.S. Navy ships were off the coast of New Georgia on the night of 5-6 July, in support of landings of ground forces. The Helena was struck by three torpedos and broken into three sections, sinking at the cost of 170 lives.