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A Day Trip to the Casco Bay Islands by Ferry from Portland, Maine
The single best cheap day out in Portland is sitting right at the end of Commercial Street, and most visitors walk past it. The Casco Bay Lines ferry terminal on the Maine State Pier runs boats to a string of inhabited islands all summer, and for the price of a sandwich you can spend a whole day on a different one. These are not resort islands. People live here year-round, the pace is slow, and the appeal is exactly that. Here is which island to pick, what to actually do once you land, and how to do it without a car.
The summer schedule runs roughly June 20 through early September, with the most frequent service of the year. Always check the current Casco Bay Lines schedule the day you go, because departure times shift by season and by island.
Peaks Island: The Easy One, and the Right First Choice
If you have never done this, go to Peaks. It is the closest island, about a 17-minute ride, with frequent ferries running from early morning to late at night, so you are never stuck waiting hours for a boat home. Round-trip fare runs around $14 for adults and about half that for seniors and kids, with a small extra charge to bring a bike.
Peaks is the one to bike. The island loop is roughly four miles, mostly flat, and you can rent a bike near the landing, sometimes on an honor-system basis, and circle the whole thing in an easy afternoon with stops. The back side of the island, facing the open ocean, is the payoff: rocky shore, almost no crowds, and the best views. You can ride to small public beaches like Centennial Beach, walk into the Battery Steele ruins of a World War II fort tucked in the island preserve, and poke into oddball little museums, including the genuinely charming Umbrella Cover Museum.
For food, keep it simple. Grab a lobster roll or a casual lunch with a water view near the landing, and get an ice cream at Down Front before the boat back. Peaks is the island that gives you the most to do with the least planning, which is why it is the standard recommendation.
Great Diamond Island: The Pretty, Polished One
Great Diamond is the dressed-up option. The big draw is Diamond Cove, a former military post, Fort McKinley, that has been restored into a tidy little village of brick buildings, a marina, and a well-regarded restaurant in Diamond's Edge. It is genuinely beautiful and feels a touch more upscale than the working-island vibe elsewhere in the bay.
Be honest with yourself about what you want here. Great Diamond is lovely for a leisurely lunch and a stroll, but it is quieter and more residential, with less to "do" than Peaks. Go if your idea of a great day is a long meal and a slow walk past handsome old buildings near the water, not if you want beaches and biking and a packed itinerary.
Long Island: The Quiet Beach Day
Long Island is the move when you want a real beach and real quiet. Andrews Beach and Big Sandy Beach are proper sandy beaches, unusual for the bay, and the island stays calm even in peak summer because day-trippers tend to default to Peaks. There is a small store and a casual spot or two for lunch, but the point of Long Island is to bring a towel, swim in cold clean water, walk the shore, and do very little. The ferry runs less often than to Peaks, so check the return times before you commit, and pad your plans so you are not racing for the last boat.
Chebeague and Cliff: The Far-Out Ones for People Who Want Less
Chebeague (say it "shuh-BIG") and Cliff are farther out and quieter still. Chebeague is the larger of the two, with a historic inn, a golf course, and good walking, and it is reachable on the Casco Bay Lines run as well as a separate faster ferry from Cousins Island in Yarmouth. Cliff is the smallest and most remote stop on the route, with almost nothing commercial and that is the entire appeal.
These are advanced picks. The ride is longer, the schedules are sparser, and there is little in the way of services once you arrive. Choose them when the goal is to genuinely unplug rather than to sightsee, and study the schedule carefully so you do not get marooned waiting for an afternoon boat.
The Mailboat Run: See the Whole Bay Without Getting Off
If you cannot decide, or the weather is iffy, ride the Casco Bay Mail Boat. It is the working ferry that delivers mail and freight to five islands (Little Diamond, Great Diamond, Long, Chebeague, and Cliff) on a loop that takes about three hours round trip. You stay aboard the whole time, watch island life happen at each stop, and get a wide tour of the bay, lighthouses and forts included, for the cost of a regular ferry ticket. It is the best-value "boat tour" in Portland precisely because it is not marketed as one. Sit on the outside deck, bring a layer because it is cooler on the water, and let the captain do the work.
How to Do It Right
A few things that separate a good island day from a frustrating one. Build your day around the return schedule, not the outbound one, since the last useful boat sets your hard deadline. Pack a layer and water, because the islands have limited services and the breeze off the bay is real even in July. Bring cash for the honor-system bike rentals and small island stores. And do not try to do two islands in one day on the regular schedule, since the connections rarely line up. Pick one, or ride the mailboat and see them all from the deck.
FAQ
What islands can you visit by ferry from Portland, Maine?
Casco Bay Lines runs ferries from the Maine State Pier in Portland to several inhabited islands, including Peaks Island, Little Diamond, Great Diamond (Diamond Cove), Long Island, Chebeague Island, and Cliff Island. Peaks is the closest and easiest at about 17 minutes, while Chebeague and Cliff are farther out and quieter. The summer schedule with the most frequent service runs roughly from late June through early September.
Which Casco Bay island is best for a first visit?
Peaks Island is the best first trip. It is the closest, has the most frequent ferries, and offers the most to do, including a flat four-mile loop you can bike, small public beaches, the Battery Steele fort ruins, quirky museums, and casual waterfront food. It is the easiest island to enjoy without much planning.
How much does the ferry to Peaks Island cost?
The round-trip fare to Peaks Island runs around $14 for adults, about half that for seniors and children, with a small additional charge to bring a bicycle. Fares and schedules are set by Casco Bay Lines and can change, so check the current rates and the day's schedule before you go.
Which Casco Bay island has the best beach?
Long Island has the best sandy beaches, including Andrews Beach and Big Sandy Beach, and it stays quieter than Peaks because most day-trippers do not make the trip. Peaks Island also has smaller public beaches like Centennial Beach. The ferry to Long Island runs less frequently, so plan your return around the schedule.
Is there a boat tour of Casco Bay that does not require getting off?
Yes. The Casco Bay Mail Boat is a working ferry that loops past five islands delivering mail and freight, a roughly three-hour round trip you can ride without disembarking. It passes lighthouses and old harbor forts and costs the same as a regular ferry ticket, which makes it the best-value scenic cruise in Portland. Sit on the outer deck and bring a layer.