FerriesLoon
Vinalhaven FerryMany of Maine's most interesting birds are in coastal waters and getting to them can be a challenge. Some of the ferries that travel to offshore islands offer birding opportunities.

Maine State Ferry Service: Several state-run ferries to offshore islands.
Casco Bay Lines: Ferry service and cruises in Casco Bay near Portland.
Monhegan Boat Line: Ferry Service to Monhegan Island.
Old Quarry Adventure: Hike and Bike service to Isle au Haut.

The Cat: A high speed ferry from Portland and Bar Harbor to Nova Scotia, this vessel replaced the venerable "Bluenose" a few years ago, reducing the crossing time by over half. Despite its speed, experienced birders have enjoyed the crossing for years because of the time and distance spent traversing waters inhabited with pelagic species.
Grand Manan Ferry
The Grand Manan Ferry is particularly good for pelagic birding. For those enjoying a "two-nation vacation," this ferry crosses a channel that is often full of Greater and Sooty Shearwaters. Northern Gannets, Black Guillemots, Razorbills, and Common Murres are sighted regularly during the 90 minute passage. Other alcids are seen more rarely, including puffins and dolphins. Red-necked Phalaropes and Black-legged Kittiwakes occur later in summer. This channel is also feeding grounds for Humpback Whales, Harbor Porpoises, and White-sided Dolphins.