Fort Blockhouse stands at the tip of the peninsula where Gosport's waterfront meets the entrance to Portsmouth Harbour. The fort itself is still in military use and not publicly accessible, but the Haslar sea wall running west from the fort is open and makes for one of the best walks in the area.
The sea wall follows the shoreline for about two kilometres, with wide views across the Solent toward the Isle of Wight on one side and back over the harbour mouth to Old Portsmouth on the other. The path is flat, exposed, and genuinely bracing on a windy day — this is the open water of the eastern Solent, not a sheltered estuary. At the southern end, near Fort Monckton, the seagrass beds are visible through the clear water at low tide, and common terns nest here in summer.