Captain John Joseph Cowan CSC, CD (born 23 July 1957) is a Royal Australian Navy (RAN) officer.
Cowan originally joined the Royal Canadian Navy (RCN) in 1976 as an ordinary seaman boatswain, eventually being commissioned as an officer in 1988, but transferred to the RAN in 1996.
John joined the Royal Canadian Navy as an ordinary seaman boatswain in 1976.
He was deployed as part of the Canadian response and support to Operation Sharp Guard for the blockade of the former Yugoslavia.
John joined the Royal Australian Navy on 8 July 1996, retaining his commission and qualification as a ships navigator.