The church exists because an earlier one did not survive. Catholic worship came to Port Douglas in 1878, and by 1881 a church stood on Port Hill under Father Pierre-Marie Bucas, a Breton priest, on land overlooking the busy gold port. Then came the cyclone of 16 March 1911, which levelled much of the town. The local paper - itself knocked out of action - reported that the church and presbytery were simply 'blown to bits.' The community rebuilt the presbytery first and held Mass there, and the new St Mary's rose in its place, completed in 1914. Its builders, short of money and far from any city, almost certainly recycled timber from the wreckage of the old - a frugal, practical faith suited to a frontier coast.

There is nothing grand about St Mary's, and that is its charm. It is a simple timber-framed building with its studwork left exposed, set on low stumps, with a steeply pitched gabled roof of corrugated iron and side walls braced by plain timber buttresses. The framing is hickory ash; the cladding was northern silky oak. A small porch at the front is lit by triple lancet windows, and inside, three lancet-shaped timber arches separate the sanctuary from the nave beneath an unlined ceiling. It is exactly the kind of church a small, isolated community built to meet its own needs - honest about its limits, and a record of how such towns coped with the cyclones that periodically flattened their timber buildings.

By the 1980s the parish had outgrown the old church, and St Mary's was in poor condition just as Port Douglas began its transformation into a booming resort. In 1987 the Catholic Church handed the building to the local community, on the condition it stay in Christian use. The townspeople rose to it. As a project for Australia's 1988 Bicentenary, they moved the entire church from Port Hill down to parkland on the foreshore in November 1988, restored it through fund-raising and volunteer labour under the Port Douglas Restoration Society, and renamed it St Mary's by the Sea. The original hilltop site was sold to fund a new parish church elsewhere. The little church was not preserved by a government or a diocese, but by a town that decided it mattered.

Today St Mary's is non-denominational, a community church given over to weddings, carol services and quiet moments by the water. Its enduring appeal is that window behind the altar, which frames Dicksons Inlet and the mountains beyond and lets the tropical light pour in. Heritage-listed since 1992, it is one of the oldest buildings in Port Douglas and one of the very few that survives from before the resort era - a glimpse of the timber town that stood here when this was a working port and not a holiday coast. People still come not only to marry but simply to sit, to watch the light move on the water through the glass, and to feel the small weight of a place a community chose, twice, to save.