Day Cruises Out of Portland Maine

Casco Bay Lines operates the oldest continuously running ferry service in the United States, its first steam-powered vessel launched in 1845.

The 56 Commercial Street terminal anchors a network spanning six year-round islands and three seasonal landings, carrying 900,000 passengers annually across routes that double as sightseeing corridors. Each departure threads past nine active lighthouses, the oldest — Portland Head Light — commissioned by George Washington in 1791 and still maintained by the Coast Guard.

The bay itself covers 136 square miles of tidal water, its 222 charted islands forming a natural breakwater that shelters Portland Harbor from Atlantic swells. Geological surveys map the archipelago as drowned drumlin hills, glacial deposits left 12,000 years ago when sea levels rose 300 feet. Indigenous Abenaki communities harvested cod and lobster here for millennia before European settlement; archaeological digs on Peaks Island uncovered shell middens carbon-dated to 2800 BCE. Colonial merchants built the first commercial wharves in 1632, and by 1850 Portland ranked as the sixth-largest port in North America, its clipper ships carrying lumber and granite to Caribbean markets.

Today's fleet includes five diesel-powered vessels ranging from the 90-passenger Machigonne II to the 399-passenger Aucocisco III. Casco Bay lighthouse cruises circumnavigate the outer islands in two-hour loops, passing Spring Point Ledge Light's cast-iron caisson tower, Ram Island Ledge's 90-foot granite shaft, and the white clapboard keeper's house on Peaks Island. Charter operators run seasonal sunset sails aboard traditional windjammers, gaff-rigged schooners restored from working cargo vessels of the 1920s. The Maine Narrow Gauge Railroad Museum preserves the island trolley network that once connected ferry landings to Victorian-era resort hotels.

Water temperatures in Casco Bay range from 38°F in February to 65°F in August. Tidal range averages nine feet, exposing rockweed-covered ledges at low water and flooding granite boat ramps twice daily. Harbor seals haul out on offshore ledges year-round; minke whales and harbor porpoises appear in the shipping channel during summer herring runs. The working waterfront still supports 150 commercial fishing vessels, their bright-painted buoys marking lobster grounds that produce six million pounds annually.