Assigned to the Naval Overseas Transportation Service, Munaires departed New York City on 27 January 1918 in convoy for Europe, arriving at Bordeaux, France, on 17 February 1918 to discharge her cargo of United States Army supplies.

Clearing Gironde, France, on 24 April 1918, she returned to the United States East Coast, arriving at New York City on 7 May 1918.

Munaires made four more round-trip runs to French ports with U.S. Army materials, mostly corn and blankets, the last of these voyages ending at New York City on 20 December 1918.

Arriving at La Plata, Argentina, on 12 February 1919, she unloaded her cargo and steamed back to New York City, which she reached on 4 April 1919.

Once again SS Munaires, she operated for the Munson Steamship Line in commercial service until she was torpedoed and sunk during World War II on 28 September 1942.