Double-breasted jacket of blue cloth featuring a wide open collar, four decorative button holes to each lapel, three decorative buttons to each breast, horizontal slash pocket either side of the waist and fittings for removable epaulettes to the shoulders. All buttons are gilt Royal Navy Officer pattern (King's Crown).
The jacket is missing the two conjoined buttons used to fasten the front of the jacket.
As stipulated by the 1945 Royal Navy Uniform Regulations, the Officer's Blue Mess Jacket could be worn with No. 2 Ball Dress (with epaulettes), No. 2A Ball Dress (without epaulettes), No. 6 Mess Dress and No. 7 Mess Undress. In September 1939, all but No. 7 Dress were suspended by Admiralty Fleet Order (AFO) 2605 for the duration of the war.