Possibly built around the 13th century, the church was founded as early as the 6th century and is a classic example of the situation of the typical early medieval Welsh church.
St Llonio's is located immediately north of the village centre, on a spur jutting into the Severn Valley, and within a fortified promontory fort, the defensive bank forming, until recently, the northern boundary of the church.
It was initially a clas structure with its western tower containing a pyramidal slate roof over a timber belfry, dating from the 13th century. It is recorded as Ecclesia de Landinam in the Norwich Taxation of 1254 with a value of £1 6s 8d.
The majority of the church was rebuilt in the 19th century, coinciding with the restoration by George Edmund Street.
The church has a wooden reredos, two old tomb recesses in the sanctuary, a damaged perpendicular font and a number of 17th century carved choir stalls. The square western tower probably dates from the 13th century with its timber belfry designed in Marches style. Rebuilding culminated in 1864-65 and left only the north wall of the chancel remaining from the previous design. During the restoration, new windows in square headed frames were inserted throughout the church.
In the centre of the burial ground, to the southwest of the church, is an ancient yew tree claimed to be around 800 years old.