In 1934, Dornier's Swiss subsidiary, based at its factory at Altenrhein, designed a three-seat, single-engined military floatplane, the Do C3; two prototypes were built,[1] with the first flown in 1935.

It was powered by a Hispano-Suiza 12Ybrs engine driving a three-bladed propeller, and could carry a single torpedo or bombs under the fuselage.

[1][2] The first production model, known as the Do 22/See when fitted with floats, did not fly until 15 July 1938 from Dornier's factory at Friedrichshafen, Germany, although it did incorporate parts made in Switzerland.

[3] The Greek Do 22s were destroyed during the German invasion of the Balkans in 1941, but the crews of eight of the Yugoslav machines successfully evaded capture or destruction by fleeing to Egypt.

There they flew under the control of the British Royal Air Force until the lack of spare parts made the aircraft unusable.