Access unclearno public right of way confirmed — check locally before setting out
Substantial ruinsruined, but plenty survives above ground
Leiston Abbey began out here on the Minsmere marshes in 1182, until repeated flooding drove the Premonstratensian canons inland to the site near the town in the 1360s. A chapel was kept going on the low island above the reedbeds, lived in by a retired abbot as a hermit until the Dissolution, and its broken walls are the only thing left of the first abbey. A WWII pillbox was built inside them. The footpath from Eastbridge towards the sluice passes close by, which is how most people see it — from the path, nothing else laid on. Dunwich is up the coast.
More at the National Heritage List entry