William Ralph Fielden was born in Bristol, Gloucestershire on 30 October 1900, the son of Clement Joshua and Ethel Fielden (née Jackson). He joined the Royal Navy as a Boy Artificer on 3 January 1916. On completion of his Engine Room Artificer apprenticeship, he was drafted to the aircraft carrier HMS ARGUS on 25 March 1920. He then served in HMS SOMME, HMS TRINIDAD, HMS WARWICK, HMS RESOLUTION, HMS P40 and HMS VENETIA. Engine Room Artificer First Class William Fielden was promoted to Warrant Engineer on 1 July 1933, and, after post promotion courses, he was appointed to the cruiser HMS EXETER on 10 October 1933.

He joined HMS DOLPHIN ‘for the Submarine Course‘ on 31 August 1936, followed by an appointment to HMS L27 as the Engineer on 28 December 1936. William Fielden was sent to Hong Kong to join HMS ROVER as the Engineer on 21 December 1938.

On 15 August 1939, William Fielden was appointed to HMS REGULUS as Engineering Officer. HMS REGULUS was at sea when War was declared having left Hong Kong on 3 September 1939 with orders to conduct a patrol to the east of the Luzon Strait. This was the first of four patrols before returning to Hong Kong in early January 1940. HMS REGULUS then took passage to the Mediterranean arriving at Alexandria in Egypt on 30 July 1940. REGULUS then completed three Patrols off the coast of North Africa from Alexandria. HMS REGULUS left Alexandria on 18 November 1940 for another Patrol, initially off Taranto in Italy, before being diverted to the Lower Adriatic and Straits of Otranto. HMS REGULUS failed to return from this Patrol and was assumed, on 6 December 1940, to have been lost with all hands.

William Fielden was the husband of Gladys Ethel Kate Fielden (née Prout). They had been married since March 1925.