Hydrus departed Providence 22 December for Hampton Roads and her shakedown training, completing this phase of her operations early in January 1945.

With the island campaign in the Pacific then entering its final phases, Hydrus sailed 1 February for Guadalcanal to participate in the extensive training operations for the projected invasion of Okinawa, the last objective before the mainland itself.

Arriving 11 February, she took part in practice landings on Guadalcanal until 15 March, when her group, Task Force 53, sailed for the final staging area, Ulithi.

The next two months saw Hydrus operate temporarily as an inter-island cargo carrier, transporting supplies of various types among the myriad islands in the Hawaiian chain.

Her role in the Chinese occupation over, Hydrus was assigned duty with "Magic Carpet", the gigantic operation for the return of Pacific veterans.

There Hydrus was selected as a training ship for the New York State Maritime Academy, and steamed up the East River to Fort Schuyler 6 March 1946.