Llanfaes Friary was a Franciscan friary in the now vanished medieval town of Llanfaes, close to what is now Beaumaris, in south east Anglesey, Wales. It was founded around 1237 in memory of Joan, wife of Llywelyn ab Iorwerth. The Friary survived the depopulation of the town, but was dissolved in 1538 and most of the buildings dismantled soon afterwards. The land became an estate on which, in 1623, Rowland Whyte built a house which he called Friars. It became one of the many properties of the Bulkeley family, and was substantially rebuilt in 1866. By the 20th century the house and grounds were owned by James Hartley Burton. In 1939 they were requisitioned for wartime use, adapting and repairing flying boats, by Saunders-Roe, who continued after the war with a wide variety of light engineering activities. The industrial uses finally came to an end in the late 1990s. An archaeological dig on the site in 1991 identified substantial buried remains of the friary church and other monastic buildings. The site is a Scheduled monument.