This round-towered church is built mainly of flint and has a thatched roof and three bells dated 1634, 1638 and 1721. The tower is early Norman in date. There are floor levels dating from the fourteenth century, a seven sacrament font dated 1485 and a fifteenth century rood screen.
The current vicar is the Rev. Peter Halls who lives in nearby Brooke and covers the five parishes of Brooke, Kirstead, Mundham, Seething and Thwaite.

Parts of the churchyard are designated as “wildlife conservation areas” because an impressive number of native wildflower species grow there in this largely unsprayed and unfertilised area. Seething is ranked amongst the top five best churchyards in the county of Norfolk in terms of species diversity. The picture shows the uncommon Pyramidal Orchid in flower on the south side of the church.

The churchyard conservation scheme is run by The Norfolk Wildlife Trust.
The church tower was covered in scaffolding and mesh for several weeks in June 1999 while a local builder repaired the tower and re-pointed the flints.