Ordered under the 1923 programme, she was the fifth ship of the Royal Navy to carry the name Oberon.

Oberon differed from the predecessor L-class submarines in that she was lengthened by 32 feet (9.8 m) and broadened by 3 feet (0.91 m), in addition to a two-knot reduction in top speed, expanded range, and double the number of torpedoes and torpedo tubes.

The submarine was propelled while surfaced by two Admiralty diesel engines rated at 2,950 brake horsepower (2,200 kW) and by two electric motors rated at 1,350 shaft horsepower (1,010 kW), each driving one propeller shaft.

Modifications made during the Second World War included the addition of an Oerlikon 20 mm cannon for anti-aircraft defense and a Type 291W radio direction finder for air and surface warning.

[4] She was laid down on 22 March 1924, launched on 24 September 1926 at the Chatham Dockyard and commissioned on 24 August 1927.