The school is extremely proud of its significant links with St Davids Cathedral.

The Cathedral is at the very heart of the community of St.Davids. There is a strong link between the school and the Cathedral as many students who attend Ysgol Penrhyn Dewi are also choristers in the Cathedral Choirs.
It is a significant honour that the school is able to hold its annual Christmas Carol Service in the nave of the Cathedral. This is one of the highlights of the school calendar.

Every year Ysgol Penrhyn Dewi comes together to celebrate the life of St David with a celebratory service held every year in the nave of the Cathedral. The Bishop of the St Davids Diocese is also always present at this service to address the children of the community.

Canon Leigh Richardson Sub-Dean and Vicar of the Parish is a very good friend to the school and regularly visits the school to conduct assemblies and talks with students.