Kea was the son of King Lleuddun Luyddog of Gododdin. He became a Cumbric bishop before moving on to be a hermit in Wales, and then Kea in Cornwall, founding churches at Street, Somerset and Landkey, Devon on the way. He was harassed by the Cornish king, Teudar, when he sheltered a deer he was hunting. Having his oxen confiscated, he used the deer to plough the soil instead. He later travelled over the Channel to Cleder in Brittany, where he eventually died.
The life also describes Kea's dealings with King Arthur. He advises the king during his conflict with the Roman emperor Lucius Hiberius, and is called upon to negotiate a peace between Arthur and his nephew Mordred before the Battle of Camlann. He criticizes Arthur's wife Guinevere for her adultury with Mordred, leading her to regret her behaviour. There have also been attempts to identify Saint Kea with the Sir Kay of Arthurian legend.