D-31

D31 or D.31 may refer to :
* Dewoitine D.31, a French
* HMAS Voyager (D31), a 1918 Royal Australian Navy W class destroyer
* HMS Arbiter (D31), a 1943 British Royal Navy escort aircraft carrier
* HMS Broadsword (D31), a 1946 British Royal Navy Weapon-class destroyer
* HMS Vigo (D31), a 1945 British Royal Navy Battle-class destroyer
* PRR D31, an American and also :
* D31 Aragua, a Venezuelan Navy Nueva Esparta class destroyer
* Benign neoplasm of eye and adnexa code