The 35 m (116 ft) high tower of St Andrew's is one of the tallest in Somerset and is an important feature in the landscape surrounding Blagdon Lake.
Built in the C15th the tower is the oldest part of the church. The chancel, nave and aisles, although C15th in style, were rebuilt in 1907–08 by Sir Frank Wills.
Above the altar is a striking painting by Oswald Moser (1874–1953) The Last Supper, purchased in 1907 for the church by Lord Winterstoke. It is unusual in English churches to have a painting behind the altar and the picture is a focal point in the chancel. The composition is in the style of Caravaggio – the models came from the unemployed on the Chelsea embankment.
The Space@St Andrew's at the back of the church is used by a wide range of community groups, and the church also hosts concerts for organists and choirs as well as other performances and festivals.
Pipistrelles and brown long-eared bats have both been recorded inside the church in the past. Surveys funded by the Bats in Churches project in summer 2021 revealed only occasional use of the church by individual common pipistrelles with no sign of the brown long-eared colony.
In July 2021 children from Blagdon Primary School visited the church to learn about bats and churches.