Designed by Mr Harbottle Reed of Exeter, the Church is of local limestone outside, in the Perpendicular style, and purple-grey Dulverton stone inside. It was designed to accommodate about 750 worshippers.

The Organ in St Simon’s Church, Plymouth was originally built by Renatus Harris in 1707 for St Peter Mancroft Church, Norwich.
It was subsequently rebuilt and enlarged by John Pike England in 1794 and again by Hedgeland in 1866.
Hele & Company built a new Organ for St Peter Mancroft in 1910.
They removed the old Organ and after much refurbishment installed it in St. Simon’s Church, Plymouth in 1912.