Gosport has no railway station — the line closed in 1953 and the old station building survives only as a listed structure. The practical options are bus, car, or ferry from Portsmouth.
From Portsmouth, take the passenger ferry from the Hard Interchange pontoon (next to Portsmouth Harbour railway station) — it runs every few minutes and takes five minutes. This is the most pleasant way to arrive.
By bus, the X4 and 1 services run from Portsmouth, Fareham, and Southampton. From London by car, take the M27 westbound and exit for Gosport via the A32; the journey is about 90 minutes from central London. Parking is available near the ferry terminal and the museums.