Borys Kozhyn was born in Pskov in 1944 in a family of the World War II veteran who was repressed in 1947 and convicted for 25 years, but in 1956 rehabilitated.

Upon graduation (August 1968 - November 1971) he was placed as a commander assistant and commander of an anti-submarine boat PR-201 (predecessor of Poti-class corvette)[1][a] (military unit 99724) that was part of the Black Sea Fleet division of ships carrying out security of water district (Russian: дивизия кораблей ОВР, divizia korablei OVR) in Sevastopol.

During that period he also served as a commander assistant of a patrol ship (Russian: сторожевой корабль) PR-159 (Petya-class frigate) (military unit 20935) in Donuzlav.

After that he was a commander of security brigade of water district (military unit 26977), Black Sea Fleet Naval base in Sevastopol.

In 1986-92 he served as a chief of staff – deputy commander of the Black Sea Fleet Naval base (military unit 99324) in Donuzlav.