The list of ship commissionings in 1884 includes a chronological list of all ships commissioned in 1884.
| Date | Operator | Ship | Pennant | Class and type | Notes |
|---|---|---|---|---|---|
| June 16 |  United States Navy | Nantucket | Passaic-class monitor | Recommissioned from reserve | |
| March 13 |  Imperial Japanese Navy | Kaimon | Sloop-of-war |