A commemorative plaque will be unveiled at the Remembrance Day service in Frome on Sunday.
The plaque of HMS Thunderbolt will be handed over by Margaret Sallis, president of the Royal Naval Association (Frome branch), to Humphrey Barnes, chairman of the Memorial Theatre Trust, to mark the 70th anniversary of the Urban and Rural District Council adopting the submarine in 1942.
The plaque was originally erected in St John's Church but was then lent by the church to the Submarine Museum. It has now been returned to St John's and will be entrusted by the church to the care of the Memorial Theatre so that it can once again be safely displayed.
HMS Thunderbolt was rebuilt from the wreckage of HMS Thetis, and was herself lost with all hands off the coast of Sicily in 1943.
The Rev Colin Alsbury is pleased that the plaque will again be displayed in the town.
He said: "I was born in Birkenhead and grew up knowing of the tragedy of HMS Thetis. My father knew the employee at the shipyard who boarded the crew and guests on to that fateful voyage in 1939.
"It was a strange coincidence to come to Frome and discover that It had adopted the reincarnated HMS Thetis as HMS Thunderbolt. It is a pleasure therefore to welcome the plaque back to Frome."
The service takes place from 10.45am outside the theatre with a parade and a two-minute silence.