Belvelly Castle, Medieval tower house in County Cork, Ireland

Belvelly Castle is a tall rectangular tower house of rough grey-brown stone blocks, standing at the edge of the water beside the bridge linking Fota Island to Great Island. Its flat top has slightly broken, uneven edges, and its front face shows a few small openings: one near the top right, a vertical slit lower down and two smaller holes below. A doorway near the base has a small window to its left, and a low stone wall partly hides the lower right corner.

Belvelly Castle is a 14th- or 15th-century tower house built by the Anglo-Norman Hodnett family. In the 14th century it was taken by the Roche and Barry families, though the Hodnetts later leased their lands back. Some sources say Walter Raleigh occupied it in the 16th century; Roger Boyle, 1st Earl of Orrery, garrisoned troops there during the Irish Confederate Wars in the mid-17th century.

The castle's Irish name, Caisleán Bhéal an Bhealaigh, refers to the mouth of the pass, matching its position beside the bridge linking Fota Island to Great Island. Local coachmen once brought sailors from Queenstown here, reputedly believing they were visiting Blarney Castle and its stone. The owners are among the sponsors of Cobh Ramblers FC.

After renovation work completed in 2018, the castle now serves as a private residence and is not open to the public. It is best to view the exterior from the water or look for views from nearby public areas.

Local coachmen during World War I brought sailors docked at Queenstown (Cobh) here, reputedly believing they were visiting Blarney Castle and its Blarney Stone. The castle was occupied and somewhat modified by the Irish Army during the Emergency of 1939–1945.