List of ship decommissionings in 1918
The list of ship decommissionings in 1918 includes a chronological list of ships decommissioned in 1918. In cases where no official commissioning ceremony was held, the date of service entry may be used instead. For ships lost at sea, see list of shipwrecks in 1918 instead.
| Date | Operator | Ship | Pennant | Class and type | Fate and other notes |
| January 2 | ' | SP-197 | Section patrol craft | Recommissioned 18 April 1918 | |
| November 15 | ' | SP-382 | Section patrol craft | Returned to pre-World War I civilian owner | |
| November 29 | ' | SP-1 | Section patrol craft | Returned to pre-World War I civilian owner | |
| November | ' | SP-1228 | Section patrol craft | Returned to pre-World War I civilian owner | |
| December 2 | ' | ID-2413 | Tugboat | returned to owner | |
| December 16 | ' | SP-197 | Section patrol craft | Returned to pre-World War I civilian owner | |
| December 19 | ' | SP-2646 | Section patrol craft | Returned to pre-World War I civilian owner | |
| December | ' | SP-208 | Section patrol craft | Returned to pre-World War I civilian owner | |
| unknown date | ' | SP-1206 | Section patrol craft | Returned to pre-World War I civilian owner | |
| unknown date | ' | ID-3434 | Section patrol craft | Sold |