Casco Bay Lines is the main ferry line that travels throughout the islands carrying passengers, vehicles and freight between Portland, and the islands of Peaks, Little Diamond, Great Diamond, Long, Chebeague, and Cliff. There's a history here. The Casco Bay Steamboat Company began providng permanent year-round service to the Casco Bay Islands in 1878. A popular myth claims that there are 365 islands in the Bay(at low tide hahaha!)), hence the name also attributed to the islands, the Calandar Islands. If you come for a visit, there are lots of different ways to see the city and the surrounding area. You might want to try the water. I've taken the Sunset Cruise, the Moonlight Run and many day trips to Peaks. All highly recommended. My suggestion? Get to Peaks and walk or bike the circular roadway that follows the water around the island. If it's a Sunday afternoon, take in the weekly Reggae Fest at Jones Landing, or any other night view the stunning sunset, over Portland, from the front deck of the Inn on Peaks Island, sipping your favorite beverage. Quite relaxing!