The original railway line for passengers from Westerfield to Felixstowe was opened by the Felixstowe Railway and Pier Company in 1877. Great Eastern Railway (1862-1948) purchased the line in 1887 and built stations at Felixstowe Town and Trimley St Mary. Other stations built by the G.E.R. included Beach Station (demolished), Orwell Station (demolished) and Derby Road in Ipswich. The line is now served with diesel railcars for passengers to Felixstowe and Freightliner traffic for the Port of Felixstowe branch line.

Trimley Station was opened on 1st May 1891 and pre-dates the Town Station at Felixstowe by seven years. The station was built in an attempt to generate good quality commuter travel into Felixstowe. It is likely now to be the only surviving country station built by the former Great Eastern Railway in Suffolk.

Trimley station was built in a 'speculative' version of the New Essex style – one of only two examples to be built outside Essex. The Chief Architect of the Great Eastern Railway, W N Ashbee, was the author of this design and the buildings became known as in the 'Ashbee style'. Ashbee was also the architect of the Town Station in Felixstowe (1898), now Grade II listed.

The interior of the station would have comprised originally of a first class waiting room, porter's lodge with first class lavatory behind, booking office, combined booking hall and general waiting room and ladies' room with lavatory en-suite.

The booking office at Trimley St Mary was closed in 1967. A passenger footbridge survives along with the Gatekeeper's House adjacent the crossing at the Station. The original Break Goods store is also extant. What may have been the Stationmaster's House also survives and has been extended. An associated signal box was demolished in 1988. A smaller passenger building formerly on the opposite side of the platform (the up platform) has been demolished (date unknown).

It is the view of officers that the Railway Station building at Trimley St Mary is a building of special architectural and historic merit. This is for the following reasons:

  •  It represents what is likely to be the sole surviving country railway station constructed by the Great Eastern Railway in Suffolk. It is only one of two examples built in the New Essex style by the Chief Architect of the Great Eastern Railway, W W Ashbee, in Suffolk;
  •  Although missing its original canopy (removed for safety reasons) and two of its chimneys the station building appears to be largely intact and unaltered;
  • It has special architectural interest in the design and quality of its building consisting of the use of an elaborate canopy; string coursing details in stone; fishscale gable tile hanging; rubbed brick round-headed arches; plain tile roof construction with decorative ridges; and original cast iron rainwater goods, all representing characteristic features of Late Victorian railway architecture; and
  • The station survives as part of a good ensemble of Late Victorian railways buildings and structures, including the original Break Goods store, Gatekeeper's House, Stationmaster's House, passenger footbridge, associated cast iron railings and gates, and platform.