The Venetian castle stands on a small wooded island just across the Vivari Channel from the main archaeological site, reached by a short ferry crossing. Its triangular plan — unusual even by Venetian standards — was dictated by the triangular shape of the island itself, and the towers at each corner give it an immediately distinctive silhouette.
Built in the 15th century and reinforced several times under Venetian rule, the castle was taken by the Ottomans in the 16th century and passed to Ali Pasha of Ioannina in the early 19th century, who added further fortifications. The walls are largely intact and the interior is open to explore, with views back across the channel to the ancient ruins and the lake beyond. The crossing on the small ferry is a pleasure in itself — the channel is narrow, fringed with reeds, and the castle appears suddenly from among the trees.