St Mary's by the Sea is a small, Gothic-style timber church situated on the foreshore at Wharf Street near the road leading to Pier 319.

The church is a timber-framed structure with exposed exterior studwork set on low timber stumps.
It has a steeply pitched gabled roof clad in corrugated iron.
The building is rectangular in plan with a vestry off the rear corner and a small central porch at the front flanked by lancet windows.
The porch has a gabled roof clad in corrugated iron and a side entrance and is lit by triple lancet windows.
The side walls are braced by simple timber buttresses.
The bearers and joists are of hickory ash and penda timbers and the framing is hickory ash.
The wall cladding was of northern silky oak although much of this and the flooring has had to be replaced.

Internally, the ceiling is unlined and three lancet-shaped timber archways separate the sanctuary from the nave.
St Mary's by the Sea is a small, Gothic-style timber church situated on the foreshore at Wharf Street near the road leading to Pier 319.
The church is a timber-framed structure with exposed exterior studwork set on low timber stumps. It has a steeply pitched gabled roof clad in corrugated iron. The building is rectangular in plan with a vestry off the rear corner and a small central porch at the front flanked by lancet windows. The porch has a gabled roof clad in corrugated iron and a side entrance and is lit by triple lancet windows. The side walls are braced by simple timber buttresses. The bearers and joists are of hickory ash and penda timbers and the framing is hickory ash. The wall cladding was of northern silky oak although much of this and the flooring has had to be replaced.
Internally, the ceiling is unlined and three lancet-shaped timber archways separate the sanctuary from the nave.
St Mary's by the Sea, Port Douglas