The original Penmaen Church, like Pennard, is said to have been besanded and abandoned in the early C14 at a time of climate change and stormy weather on the south coast of Gower. The site was on the Burrows not far from that of Penmaen Old Castle on the headland above Three Cliffs Bay. The church remains are largely buried today but two high grassy banks are said to represent the fortifications of a simple C12 motte and bailey castle which is marked on maps. A mediaeval censer found at the 1861 church excavations is housed in Swansea Museum. An alternative view is that the church was moved in the C13 to make way for the mediaeval hunting park for Parc le Bros.
Sometime in the C14 a new Gothic-style church was located some distance inland on the main South Gower road and was dedicated to St John the Baptist, the patron saint of the order of the Knights Hospitallers of St John of Jerusalem who had held the living of the old church as well as that of several others in Gower.
In the years 1854-5 the church underwent a major restoration and was almost completely rebuilt in the Early English style, leaving little trace of the early Gothic fabric. Bath stone was used extensively for window tracery and dressings as well as for a new pulpit. A totally new roof was of Bangor slates. The cost of restoration was £500 raised by local subscription, under the enthusiastic leadership of the Rector, the Revd. Edward Knight James. In the north wall of the north aisle are two lancet windows depicting the figures of St John the Baptist and St Paul, erected by parishioners and friends in memory of the same Rector who served the parish for 45 years between 1850 and 1895. At this time a beautiful stained glass window on the south side of the nave was presented to the church by William Goldsmid of London.
The church consists of a chancel with sanctuary, the nave and a short north aisle and the south porch. The chancel is lit by a three-light ornate east window and by two lancets on the south side. With the exception of one high-level window in the north aisle, all the windows in the nave are of stained glass. Mural tablets of the C17th and C18th inscribed in Latin on the chancel walls commemorate early rectors of the parish. The font near the porch on the south side of the nave has an octagonal bowl in a similar stem.
During the C19 restoration of the church two ancient tombstones were discovered under the altar and these were placed on the north wall of the chancel. They are the earliest monuments in the church. One dated 1623 traces the ancestors of a family called David back to Iustin ap Gwrgan, a Lord of Glamorgan in the C11. The other commemorates Richard Davies who lived at Long Oaks or Llwyn Ox in the C17, was twice High Sheriff of Glamorgan in the 1660’s and his inscriptions bears the arms of the same Iustin ap Grwrgan. The ancestry of several local families today has been traced back through him to the C11 and even further.
On the outside is a small bellcote located over the chancel arch and this houses a single bell which is thought to have been cast by itinerant bell-founders. The bell is devoid of any inscription or bell-founders’marks.
Local landowners in the parish, including the Vivians of Parc le Breos and the Bostocks from Penmaen House, are remembered in tablets and stained glass windows in the church. The Vivians, renowned for their philanthropy, were early industrialists who contributed much to the growth of C19 Swansea becoming ‘Copperopolis’, the copper capital of the world. An interesting member of the Bostock family was Eliza (Elizabeth) Anne Bostock (1815-1895) who is buried in the churchyard. A trustee and later an Honorary Principal, she made a significant contribution to the establishment in 1849 of the former Bedford College, the first Higher Education college for female students in the UK, which in 1900 became part of the University of London.