Cabrits National Park occupies the volcanic peninsula immediately north of Portsmouth. The headland rises steeply from the sea and is flanked by two beaches — Douglas Bay on the north side and Prince Rupert Bay to the south — giving it the character of an island just barely attached to the main coast. The park protects a substantial area of forest, and the snorkelling in Douglas Bay is excellent, with coral and reef fish accessible from shore.
The main historical draw is Fort Shirley, the restored Georgian military complex that sits on the peninsula's heights. The walk up through the trees takes about 20 minutes from the entrance, with views opening progressively over the bay and the coast to the south. Entry to the park is EC$5; a guide isn't necessary but adds context to the fort's layout.