It is not clear how or why he made his way south to the West Country but he probably first became a monk at Ynys Witrin Abbey (Glastonbury Abbey) in Somerset, later turning to the life of a hermit as nearby Lantokay, the area of Street, now called Lower Leigh. Breton legend says that an angel told him in a dream to build himself a chapel where his trusty bell first sounded. Kea had no bell, so went to see St. Gildas, presumably on Ynys Echni (Flatholm), in the Bristol Channel, and asked him to make him one. He then presumably moved on to Landkey in North Devon where the bell did not sound. So he travelled further west to Ros Ynys (Roseland) in Kernow (Cornwall) and then across the Truro River where the bell rang at Landegea, now Old Kea (just south of Truro).

So Kea settled down to a solitary existence once more. His life was, however, not as peaceful as he had hoped, for he was continually persecuted by the local King, Teudur. Kea once hid a mighty stag which Teudur was hunting in Ros Ynys. When the King took away the saint's oxen in revenge, Kea used deer instead. Later, Kea fled to Brittany and established a monastery at Cléder, west of St. Pol-de-Léon. His holy well may still be seen there today. The story that he returned to Britain in order to broker peace between King Arthur and his nephew Mordred is erroneous and due to confusion with Arthur's traditional foster-brother, Kay. It is sometimes claimed that he was buried at Lligwy on Ynys Mon (Anglesey) but the more traditional site - a chapel in the corner of the churchyard, since demolished, in Cléder - seems more likely.

Records of St. Kea date back to at least the 11th century, although the date of his Breton 'Life' is unknown. He could well be historic.