After the fall of France, she operated out of Puerto Rico with a force guarding against hostile action by a Vichy-inclined admiral commanding the French West Indies fleet based at Martinique and Guadeloupe.

Three months later, while escorting Memphis and a merchant ship to Ascension Island, Moffett made contact with U-604, and again joined Navy aircraft to attack.

In the dark and confusion of action, a friendly aircraft mistaking Moffett for the enemy made two strafing runs which caused minor damage.

On 26 March 1944, Moffett sailed as escort commander of Convoy YN-78, a group of tugs, barges, and patrol craft en route to England for the invasion of Normandy.

Laying smoke to protect the convoy, Moffett went into a series of brilliant tight turns and maneuvers to dodge the torpedo planes which continued to attack through the night, and with other escorts drove them off with antiaircraft fire.