Constantine Church stands in the centre of the village and the parish, at the top of a ridge where it commands a view to the south, to the creeks of the Helford River.
It has a chancel, a nave, two aisles and an additional north aisle, perhaps originally a chantry chapel, known as the Bosahan aisle.
The present church dates from the 15th century, except for the chancel which was rebuilt in the 19th century. There are a few fragments of an earlier Norman building to be found.
The church contains many interesting features: for example, traces in the Bosahan aisle of a late medieval wall painting, fragments of a wooden rood screen, a fine Elizabethan chest, a brass monument, also from the Elizabethan period, to Richard Geyrveys and his wife Jane, neé Trefusis, some plate, and a new window in the Lady Chapel.