The Short Answer
Most visitors end up on one of three ferry systems: Casco Bay Lines running year-round from Portland to the Casco Bay islands, the Maine State Ferry Service operating between Rockland and the Penobscot Bay islands of Vinalhaven and North Haven, or one of the day-trip boats out to Monhegan Island from Port Clyde or New Harbor. A fourth option, the Cat high-speed ferry between Bar Harbor and Yarmouth, Nova Scotia, runs seasonally for travelers extending their trip into Canada. The full Maine Travel Guide covers how the islands fit into a broader coast trip, and the Best Time to Visit Maine page explains how seasons affect ferry frequency and island conditions.
Car transportation exists on some routes but costs significantly more than foot-passenger fares, requires advance reservations, and fills weeks or months ahead in summer. Most island day trips work fine without a vehicle, and some of the smaller islands have no real road infrastructure anyway. If you plan to stay overnight on any island, book lodging and ferry tickets as early as you can, especially for July and August.
Casco Bay Lines and the Portland Islands
Casco Bay Lines operates year-round from its terminal at 56 Commercial Street on Portland's working waterfront, connecting Portland to six inhabited islands: Peaks, Little Diamond, Great Diamond, Long Island, Chebeague, and Cliff. Peaks Island is the closest and most visited, a roughly 20-minute crossing from Portland, with round-trip fares estimated at $8–12 per person. Bikes cost a small additional fee and are worth bringing to Peaks, which has a road circling the island, a rocky beach at the far end, and the remains of a former military battery above the shore. The mail boat run circles several islands in about three hours without disembarking passengers and functions as both daily postal service and a budget scenic cruise that tourists have been riding for decades.
Chebeague Island and Long Island are farther out, roughly 45–60 minutes each way, with less visitor infrastructure and more of a working-community feel. Chebeague has a small inn and some rental cottages. Long Island has almost no lodging for overnight visitors. If you are doing a same-day round trip from Portland, Peaks fits easily into a half day. Chebeague or Long Island works better as an overnight or full-day outing. Casco Bay Lines publishes its complete schedule at cascobaylines.com, with frequencies dropping noticeably in the off-season months of November through April.
Maine State Ferry Service: Penobscot Bay Islands
The Maine State Ferry Service runs from Rockland, about 85 miles north of Portland on Route 1, to Vinalhaven (approximately 75 minutes each way) and North Haven (approximately 70 minutes). A separate route departs from Lincolnville, about 35 miles north of Rockland, to Islesboro (approximately 20 minutes). Foot-passenger fares are estimated at $10–14 round trip per person depending on the route. Taking a car adds an estimated $30–50 or more each way and requires a reservation that fills weeks ahead for summer sailings. Most day visitors skip the car entirely and either rent bikes on Vinalhaven or simply walk the island roads.
Vinalhaven is the largest of the three islands, with a working lobster harbor, a few restaurants, bike rentals, and trails to the quarry ponds at Booth Quarry and Lawson's Quarry where locals swim on warm summer days. North Haven is quieter, with a long-established summer colony and fewer amenities on a quick visit, it rewards those who stay at least one night. Islesboro is a narrow, mostly residential island with a mix of older summer estates and year-round fishing families. Rockland itself is worth a stop: the Farnsworth Art Museum and a solid row of restaurants sit within walking distance of the ferry terminal at the foot of Main Street.
Monhegan Island Day Trips
Monhegan Island sits about 10 miles offshore from Port Clyde, the village at the end of Route 131 off the St. George Peninsula in the MidCoast. The Monhegan Boat Line runs the Laura B and Elizabeth Ann year-round from Port Clyde, with the crossing taking roughly 70 minutes. Hardy Boat Cruises, based in New Harbor about 25 miles away by road, runs seasonal trips of similar length from late May through early October and is a practical option if you are coming from the Boothbay Harbor side of the coast. Round-trip fares to Monhegan are estimated at $35–50 per person. Monhegan has no regular car traffic, 17 miles of hiking trails across its forested interior and exposed cliffs, and a long reputation as a painters' colony that dates to the late 1800s.
Whitehead and Blackhead on the island's eastern edge are the trail highlights: 150-foot cliffs above open Atlantic surf. Plan to be on the first morning boat and allow four to five hours on the island before catching the afternoon return. Lodging exists, a few small inns and rental cottages, but books many months in advance for summer. For a sense of what to budget, Maine trip cost planning estimates the full Monhegan day trip at roughly $80–120 per person including round-trip fare, lunch, and incidentals.
Bar Harbor Area Ferries and the Nova Scotia Connection
From Northeast Harbor on the quieter western side of Mount Desert Island, a small seasonal ferry serves the Cranberry Isles, Little Cranberry and Great Cranberry, with roughly 20-minute crossings and fares estimated under $25 round trip. These islands are small and residential, with walking trails, a one-room historical museum on Little Cranberry, and a low-key summer feel. The crossing is worth doing on a clear day as a morning excursion when you are basing yourself in the Bar Harbor area.
The Cat, a high-speed catamaran ferry, runs seasonally between Bar Harbor and Yarmouth, Nova Scotia, typically from late May through late October with one sailing per day in each direction. The crossing takes about 3.5 hours. Foot-passenger fares are estimated at $120–160 one way per person, and vehicles can be transported as well. Reservations are required and are handled through Bay Ferries at ferries.ca. If you are combining a Maine coast trip with Atlantic Canada, this is a much cleaner option than backtracking south and driving all the way up through New Brunswick.
Practical Tips
Build ferry schedules into your itinerary before you finalize anything else. Maine's ferries all reduce frequency outside of summer, some routes dropping to just two or three departures a day in the off-season. The Maine State Ferry Service (maine.gov) and the Monhegan Boat Line (monheganboat.com) both publish their seasonal timetables online. Hardy Boat Cruises typically runs Monhegan trips from late May through early October. Weather cancellations are a real risk on exposed crossings like Monhegan, particularly in fall and early spring, so build flexibility into any plan that depends on reaching that island on a specific date.
If your base is the southern Maine coast, Ogunquit, Wells, or Kennebunkport, the island ferries are less convenient than they look on a map. Portland and Casco Bay Lines are roughly 40–70 miles north of the beach towns, and Rockland is 100 miles up Route 1, which moves slowly in summer. Factor transit time both ways into your planning. The best time to visit page helps you weigh timing against the logistics of ferry-dependent side trips across the full range of Maine's seasons.
Frequently asked questions
Do I need a reservation to take the Casco Bay ferry from Portland?
Foot passengers on Casco Bay Lines generally do not need reservations. Buy a ticket at the 56 Commercial Street terminal in Portland or online and board at your departure time. Bike reservations are recommended in summer when the ferries fill up. Vehicle transport is available to some islands but is limited and should be confirmed directly with Casco Bay Lines before you drive to the dock.
How far ahead do I need to book a car on the Maine State Ferry to Vinalhaven?
For foot passengers, you can usually buy tickets the day of travel, though arriving early at the Rockland terminal is smart in July and August. Vehicle reservations are a different matter. Summer car slots fill weeks or months ahead, and showing up with a vehicle without a reservation is a gamble that rarely pays off. Book vehicle space as early as the reservation window opens on the Maine State Ferry Service website at maine.gov.
Is Monhegan Island worth visiting for just a day trip?
For most people, yes. The cliff trails on the island's eastern edge at Whitehead and Blackhead and the quiet village at the center are the main draws, and you can cover the highlights in four to five hours. Day trips work well from late May through October. Off-season trips are possible but much less frequent, and weather cancellations are more common. Book the first morning departure from Port Clyde or New Harbor to maximize time on the island.
When does the Bar Harbor to Nova Scotia ferry run, and how much does it cost?
The Cat typically operates from late May through late October with one sailing per day in each direction between Bar Harbor and Yarmouth, Nova Scotia. The crossing takes about 3.5 hours. Foot-passenger fares run an estimated $120–160 one way per person, and vehicles can also be transported. Reservations are required and are made through Bay Ferries at ferries.ca. The schedule, exact fares, and vehicle rates are updated each spring on their website.
What is the cheapest way to visit a Maine island for the day?
The Casco Bay Lines run from Portland is the most affordable entry point. A round-trip foot-passenger ticket to Peaks Island runs an estimated $8–12 per person, the crossing is only about 20 minutes each way, and you can explore the island on foot without renting anything. If you want a longer island with more hiking, the Penobscot Bay ferries to Vinalhaven or North Haven from Rockland are the next step up, with round-trip fares estimated at $10–14 per person for the 70–75 minute crossing.