Washington State Ferries (WSF) operates car and passenger ferry service in the state of Washington. It runs ten routes serving 20 terminals located around Puget Sound and in the San Juan Islands. Pets in carriers are allowed in interior passenger areas on vessels. Uncaged, unrestrained pets are not allowed to remain in interior passenger areas for the duration of a voyage. In some cases, leashed pets may transit though interior areas in order to access exterior passenger areas. WSF recognizes that it is impractical to require walk on passengers and their leashed pets to remain on the auto deck for the duration of a voyage. In order to provide shelter to these patrons, walk-on passengers with leashed pets are allowed in terminals and to board vessels and remain in exterior passenger areas, including shelter decks, promenade decks and/or sun decks at the following terminals: Bainbridge Island, Bremerton, Colman Dock, Edmonds, and Kingston. At all other terminals passengers may gain access to exterior passenger spaces of the vessel via the interior cabin provided they do not linger in an interior space and use the most direct route when moving to or from the exterior area. Walk on passengers with pets who choose to remain on the auto deck must stay with the animal for the duration of the sailing and ensure it is properly restrained. All livestock are required to travel in a vehicle when boarding the vessel.
More information on the Washington State Ferries pet policy