By car, bike or bus, highway 155 to Hisingen/Öckerö. The free car ferry (12 minutes) to Hönö/Öckerö or Björkö (6 minutes). The bus goes from the Nils Ericson bus terminal in central Gothenburg to the ferry terminal at Lilla Varholmen.

http://www.vastsverige.com/en/Ockero-islands/