The ruins of a 16th-century Portuguese fort on Tarout Island, connected to Qatif by a series of causeways across the shallow bay. The castle sits on a prominent mound in the centre of the island and is one of the few visible reminders of the Portuguese presence in the Arabian Gulf — most of what they built here was swept away by the Ottomans and later rulers. Only two towers remain standing, but the site commands a view over the island and the surrounding water.
The island itself is worth exploring: it has its own village, traditional fishing boats, and old date palm groves that feel worlds away from the industrial infrastructure of the nearby coast. Getting to the castle requires a short drive across the causeway from Qatif.