At the end of 1916 the RFC recognized the immediate need for new training planes if it were to fulfill its commitment for expansion. It realized that there was an immediate need for an aircraft, which was safe to fly, capable of quick and easy production, and easy to repair.

Capt. Geoffrey de Haviland responded to this request with a 2-seat tractor biplane, of very elemental design, with a communal cockpit. The fuselage was in two parts--the front part covered in plywood and the rear section of conventional wooden box-girder construction. The square-ended wings were of conventional construction with the upper and lower wings being interchangeable. The aircraft was powered either by the RAF 1a or the Curtiss OX-5 engine. By the end of 1917 the D.H. 6 was replaced as a trainer by the Avro 504K.

At the end of January 1918 the Admiralty requested additional aircraft to perform submarine patrols of the coastal waters from the Tyne to the Tees. At the end of March 1918 two Flights of D.H. 6's were supplied. They were based at Cramlington. Eventually 23 Flights of D.H. 6's, a total of 192 aircraft, were used in this role. Five of these Flights were used by the U.S. Navy in patrols off the Irish Coast.