Old Romney, only aboun 3.0 km inland from New Romney, lies on what was once an island in the former estuary of the River Rother.

The parish dates back to ancient times when Old Romney commenced the primitive settlement of Romney Marsh. St Clement's Church is built on an artificial mound to protect it from floodwater. It is thought the original church was built here in the 8th century.

In the 11th or 12th century the Saxon church was replaced by an early Norman church, aisleless and with a square-ended chancel. It was enlarged in the 13th century. The present building, mostly of the 13th century, has a nave and chancel, and there are north and south chapels. There is a small tower, with south-east and south-west buttresses, in the south-west corner, and a north porch.

The baptismal font is unusal. It is dated to "around 1300" and the upper part looks from the design and the colour a bit like a Tournai font, but it is made from rough local Purbeck stone. The adorned pillars seem to be younger.