The thread title says it all really.

Looking for information etc of British subss serving at or sailing our of Penang prior to WW2

Regards

Andy H

It was the 4th Submarine Flotilla that served in the Far East, usually based at Hong Kong, although they would have called at Penang.

From 1920 - based on depot ship TITANIA - ‘L’ class boats - seems to have been L.1,  L.2, L.3, L.4, L.5, L.7, L.8, L.9, L.15, L.19, L.20, L.27 and L.33.
The squadron was reduced to six boats from 1928 (those remaining were L.3, L.15, L.19, L.20, L.27 and L.33.   These were withdrawn and returned home in 1929.

From July 1930 squadron reconstituted around depot ship MEDWAY and consisted on O and P class boats - OSIRIS (to ‘38); OSWALD (to ‘35); OLYMPUS, ORPHEUS, ODIN and OTUS (all to ‘39).
POSEIDON (to ‘31 - lost); PANDORA, PARTHIAN, PERSEUS, PHOENIX, and PROTEUS (all to ‘40).  
These were joined by:
RAINBOW in 1932 (to ‘39)
REGENT in 1935 (to ‘40)
REGULUS in 1935 ( to ‘40)
ROVER in 1935 (to ‘40)