USS Onyx (PYc-5), was a diesel coastal patrol yacht of the United States Navy during World War II.

The ship was built in 1924 as Janey III by Consolidated Shipbuilding Corp. of Morris Heights, New York, and was subsequently renamed Rene and Pegasus.

Sailing again, she reached New Orleans on 5 April to report for duty to Commandant 8th Naval District.

Onyx performed services for ComEight as a coastal patrol vessel around the Gulf area until January 1942.

Beyond economic repair, her ordnance was removed and she was placed out of commission, in service, retaining her name and designation, on 15 May 1944.