While undergoing field training in the Central Training Area on Okinawa, Japan, Sergeant Dibblee was directing his team in a stream crossing when he observed one team member disappear beneath the surface. With full knowledge of the serious hazards involved and with complete disregard for his own personal safety, he entered the deep[, murky water and executed several dives in an attempt to locate and rescue the submerged Marine.

Although fatigued from the repeated dives, Sergeant Dibblee continued his efforts until he located what he declared to be the stricken team member. Upon his final descent, Sergeant Dibblee never re-surfaced, but succumbed in the deep water.

By his courageous and prompt actions in the face of great personal risk, Sergeant Dibblee sacrificed his own life in an effort to save the life of another; thereby reflecting great credit upon himself and upholding the highest traditions of the Marine Corps and the United States Naval Service.