The Oberon class was a ship class of 27 British-designed submarines operated by five nations. They were designed as a follow-on from the Porpoise class; physical dimensions were the same but stronger materials were used in hull construction and improved equipment was fitted.

The Porpoise class was an eight-boat class of diesel-electric submarines operated by the Royal Navy. This class was originally designated patrol submarines, then attack. They were the first conventional British submarines to be built after the end of World War II. Their design was, in many ways, influenced by the German World War II-era Type XXI U-boats.