For the coastal town and a municipality in southwestern Slovenia please see Piran (Italian Pirano)

Saint Piran or Perran (traditionally in Cornwall saints are simply named, without this title) is the patron saint of tin-miners. He is also generally regarded as the patron saint of Cornwall, although Saint Michael and Saint Petroc also have some claim to this title. Saint Piran's Flag is a white cross on a black background. St. Piran's Day is March 5th.

He is the most famous of all the Irish saints who came to Cornwall. He is said to have discovered tin

It is said that at his death the remains of the Blessed Martin the Abbot which he had brought from Ireland were buried with him at Perranzabuloe; his own remains were subsequently exhumed and redistributed to be used as reliquaries. Exeter Cathedral was reputed to be the possessor of one of his arms, while according to an inventory, St. Piran's Church, Perranzabuloe, had a reliquary containing his head and also a hearse in which his body was placed for processionals.

The town of Perranporth ('Piran's Port' in Cornish) hosts the annual inter-Celtic festival of , which is also named in honour of him.

St. Piran's Day is very popular in Cornwall and the term

The largest St. Piran's Day event is the March across the dunes to St. Piran's cross which thousands of people attend, generally dressed in black, white and gold, and carrying the Cornish Flag. A play of the Life of St. Piran, in Cornish, has been enacted in recent years at the event. Daffodils are also carried and placed at the cross. Daffodils also feature in celebrations in Truro, most likely due to their 'gold' colour. Black, white and gold are colours associated with Cornwall due to St. Piran's Flag (black and white), and the Duchy Shield (gold coins on black).

Legend: The heathen Irish tied him to a mill-stone, rolled it over the edge of a cliff into a stormy sea, which immediately became calm, and the saint floated safely over the water to land upon the sandy beach of Perranzabulo in Cornwall, where his first converts to Christianity were animals.

Legend: St. Piran "rediscovered" tin-smelting (tin had been smelted in Cornwall since before the Romans' arrival, but the methods had since been lost) when his black hearthstone, which was evidently a slab of tin-bearing ore, had the tin smelt out of it and rise to the top in the form of a white cross (thus the image on the flag). Sankta Piran Pyran