Using public transport:
Marstrand express from Nils Ericsson Terminal in Gothenburg.
alternatively, Train via the Bohus Line (Bohusbanan) to Ytterby station. Change for the Marstrand express. Rökan bus stop. Walk down under the bridge to the ferry terminal.
Leave the E6 at Kungälv for Marstrand. Drive towards Marstrand for around 15 km. The road sign for the ferry to Dyrön is just before the Instöbron bridge. The parking at Rökan is just beneath the bridge abutment on the mainland. Easy parking close to the ferry. Parking payable at meter during the summer season.