This list of Welsh saints includes Christian saints with Welsh connections, either because they were of Welsh origin and ethnicity or because they travelled to Wales from their own homeland and became noted in their hagiography for their work there.^[1]

The pagan Celts of Britain had already been extensively Christianized during the Roman period: although only four victims of Diocletian's persecution are now known (Saints Alban, "Amphibalus", and Julius and Aaron),^[2] Britons met the pagan Saxon invaders largely as Christians prior to being driven back to Wales, Cornwall, and Brittany. The family of Vortigern, which continued to hold Powys in the early medieval period, produced numerous saints. Although they largely refrained from missionizing among the Germans, Welsh refugees and missionaries were responsible for the Christianization of Ireland^[3] and Brittany.^[4]

The title of "saint" was used quite broadly in the Celtic churches. Extreme cases are Irish accounts of Gerald of Mayo's presiding over 3300 "saints" and Welsh claims that Bardsey held the remains of 20 000.^[6] More often, the title was given to the founder of any ecclesiastical settlement, which would thenceforth be known as their llan. Such communities were organized on tribal models: founding saints were almost invariably lesser members of local dynasties and their successors chosen from among their kin. The golden age of such establishments was the 6th century, when the "Three Saintly Families of Wales"—those of the invading Irish Brychan and Northerners Cunedda and Caw—displaced many of the local Silurian rulers in favor of their families and clans.^[7] By some estimates,^[8] these traditions produced over 800 pre-congregational saints venerated locally in Wales, but invasions by Saxons, Irishmen, Vikings, Normans, and others destroyed many ecclesiastical records. Similarly, the distance from Rome, suspicion of Celtic Christianity, and the relative disconnect of the local sees from Rome has left only two Welsh saints in the General Roman Calendar: Saints David (Dewi) and Winifred (Gwenffrewi).

• 29 May: The translation of Saint Dyfrig^[20]
• 6 June: Y Trisaint, the Three Saints^[20]
• 22 June: The decollation of Saint Winifred^[20]
• 26 June: The translation of Saint Brynach^[20]
• 1 or 2 July: Gwyl y Gwlaw^[24]
• 9 September: Gwyl y Ddelw Fyw, the Living Image^[17]
• 23 September: The ordination of Saint Padarn^[17]
• 21 October: Gwyl y Gweryddon, the Eleven Thousand Virgins^[17]
• 3 November: The translation of Saint Winifred^[16]
• 11 December: Dydd Ilas Llywelyn, the day on which Llywelyn was slain^[30]

• Children of Brychan
• List of Breton saints
• List of Cornish saints
• List of Irish saints
• List of Anglo-Saxon saints
• List of Northumbrian saints