Resuming her coaling operations with the Atlantic Fleet, Vulcan ranged from Portsmouth, New Hampshire, to Guantanamo Bay, Cuba, and from Melville, Rhode Island, to Vera Cruz, Mexico.

In addition to carrying coal, she also transported stores and ordnance supplies for the Atlantic Fleet Cruiser Squadron.

After hostilities ended, the collier was transferred to the Naval Overseas Transportation Service on 2 January 1919 and served that organization until she was returned to the Fleet Train on 23 June.

Sailing five days later, she reached Naples on 3 April but soon got underway for Gibraltar to discharge cargo and passengers.

After returning to New York on 30 April, Vulcan was decommissioned at the Norfolk Navy Yard on 20 July.