Casco Bay Lines: Islands, Ferries & What to Do

What Casco Bay Lines actually is

The Casco Bay Island Transit District operates year-round service from the ferry terminal on Commercial Street in Portland to Peaks Island, Little Diamond, Great Diamond, Long Island, Chebeague Island and Cliff Island. Some runs carry vehicles; most passengers walk on. Bicycles are carried for a fee and are the single best decision you can make on any of these islands.

Because it is transit rather than tourism, the schedule is denser in the morning and late afternoon — when islanders commute — and thinner in the middle of the day. Peaks Island gets by far the most departures. The outer islands may get only a handful, and the practical consequence is that missing a boat off Cliff Island is a much bigger problem than missing one off Peaks. Check the current timetable before you go rather than assuming a return will be along shortly.

Fares, schedules and vehicle reservations are all on the Casco Bay Lines website, and they change seasonally. Summer weekend morning boats to Peaks fill; get there early enough to be in line rather than watching from the dock.

Which island to pick

Island	Getting there	Best for
Peaks Island	Casco Bay Lines, most frequent run, about twenty minutes	First-time visitors, half-day trips, bike loops
Great Diamond / Diamond Cove	Casco Bay Lines	A quiet lunch and a former army post turned village
Long Island	Casco Bay Lines	Beaches and almost no infrastructure
Chebeague Island	Casco Bay Lines, or the separate Cousins Island ferry from Yarmouth	Overnight stays, walking, an actual island community
Cliff Island	Casco Bay Lines, end of the line	The full mailboat experience; very little on shore
Bailey and Orrs Islands	By car through Harpswell — no ferry	Lobster on the water, the cribstone bridge, coastal trails

The last row matters more than people expect. Bailey Island and Orrs Island sit in Casco Bay but are connected to the mainland by road, which means you drive there and the whole ferry question is irrelevant. Several of the best things in the bay are on that side.

The best stops on the Casco Bay islands, ranked

Ranked by rating multiplied by review volume, which is a better measure than rating alone — a perfect score from a dozen people says less than a strong score from a thousand. All figures are from our Casco Bay places data.

1. Cook's Lobster & Ale House, Bailey Island

4.4 from 1,427 reviews, 68 Garrison Cove Road. The most-reviewed place on any island in the bay by a wide margin, sitting on its own wharf at the end of the road with water on three sides. It is a big, busy, unsubtle operation and the ratings reflect that — 4.4 is good, not exceptional, and the complaints are about waits and volume rather than the food. Go for the setting, which is genuinely hard to beat, and go off-peak.

2. Giant's Stairs and McIntosh Lot Preserve, Bailey Island

4.7 from 532 reviews, 19 Ocean Street. A short shoreline trail along a shelf of rock that drops toward the open ocean in a set of natural steps. It takes half an hour and it is the best free thing on Bailey Island. Parking is a handful of spaces on a residential street; be respectful about it or there will eventually be none.

3. Battery Steele, Peaks Island

4.6 from 324 reviews. An enormous World War II gun battery sunk into the middle of Peaks Island, its concrete corridors now dark, damp, and layered with graffiti and installation art. About twenty minutes on foot from the ferry landing, or five by bike. Bring a real flashlight — the central passage is genuinely black and the floor is uneven.

4. The Cockeyed Gull, Peaks Island

4.4 from 312 reviews, 78 Island Avenue. The island's main sit-down restaurant, a few minutes up from the landing, with a deck facing the water. It is the practical answer to "where do we eat on Peaks" and it gets slammed on summer weekends. If you are on a tight ferry connection, do not start a meal here.

5. Bailey Island Beach

4.8 from 200 reviews, 2391 Harpswell Islands Road. Small, rocky-edged, and the highest-rated beach in the bay. It is not a broad sand crescent — expect a pocket cove — but the water is clear and the crowd is thin compared with anything on the mainland.

6. Bailey Island Bridge

4.9 from 187 reviews, Harpswell Islands Road. The cribstone bridge: granite blocks stacked open, without mortar, so the tide runs through it. The highest-rated structure in Casco Bay and, as far as anyone can establish, the only bridge built this way. There is a small pull-off at each end; the view is better from the Orrs Island side.

7. Fort Gorges

4.8 from 133 reviews. The abandoned granite fort on Hog Island Ledge, visible from the Eastern Promenade and from every ferry that leaves Portland. There is no scheduled service to it — you get there by kayak or your own boat, and you land on a beach and walk in. Empty, roofless, and the most atmospheric ruin in the bay.

8. Ram Island Ledge Light Station

4.6 from 46 reviews. The grey granite tower on a ledge off Cape Elizabeth, marking the northern edge of the ship channel. You cannot land on it. You see it well from the outbound ferries and even better from Portland Head Light across the water.

9. Fowler Beach, Long Island

4.7 from 35 reviews. A sand beach on Long Island, a short walk from the ferry landing, and about as close as Casco Bay gets to having a beach to yourself. Facilities are minimal to nonexistent. Bring what you need and take it back with you.

10. Midcoast Charters, Bailey Island

5.0 from 30 reviews, 68 Garrison Cove Road. A small charter operation working out of Garrison Cove. A perfect rating on thirty reviews is a small sample and should be read as such, but it is the highest-rated water-based operator on the islands in our data.

11. Eagle Island State Historic Site

4.6 from 25 reviews. Robert Peary's summer home on a small island off Harpswell, preserved as a state historic site, reachable only by boat. Seasonal and dependent on weather and operators; confirm access on the Maine state parks site before planning around it.

A note on Little Beach

Little Beach on Peaks Island appears in our data at 4.8 from just 4 reviews. That is not enough to rank on, and we have left it out of the numbered list for that reason. It is a pleasant pocket of shore, not a destination.

The mailboat run, if you only have three hours

Casco Bay Lines runs a route that calls at several islands in sequence, unloading freight and passengers at each. You can ride it without getting off. It is the cheapest boat tour in Maine, it goes places no tour boat goes, and you see the working side of the bay: lobster boats, ferry landings, cottages that can only be reached by water, the fort on its ledge.

What it is not is comfortable in bad weather, and it is not narrated in the way a tour is. Sit outside if you can. If the wind is up, take the earlier and shorter Peaks run instead and walk the island.

The sunset departure in the warm months is the one locals actually take. It fills.

Doing Peaks Island properly

Peaks is the default and it deserves to be. The crossing is about twenty minutes, the boats are frequent enough to treat as transit, and the island is a manageable loop of four or five miles on a road that runs right around the shore.

Rent a bike or a golf cart near the landing, or bring your own bike on the ferry, and do the loop counterclockwise so the back shore — the open, rocky, east-facing side — comes at the halfway point. Stop at Battery Steele on the way. Eat before the return boat rather than after, and give yourself a buffer: the last afternoon departures are the busiest of the day.

If you want to stay out there overnight, the Inn at Diamond Cove on Great Diamond Island is the one full-service property on the ferry-served islands. Chebeague has a small inn and its own ferry from Cousins Island in Yarmouth, which is the easier approach if you are driving up from the south.

Practical notes

• Terminal and parking. The ferry terminal is on Commercial Street in the middle of the Portland waterfront. There is a garage attached, and it fills on summer weekends. Park in a downtown garage and walk if it is full.
• Bikes beat cars. Taking a vehicle requires a reservation, costs a great deal more, and is unnecessary on every island a visitor would go to. A bike transforms Peaks, Long and Chebeague.
• The islands are residential. Most of what you see is somebody's house and somebody's driveway. Roads are narrow, there are few public restrooms, and there is no shop on some of the outer islands at all.
• Weather cancels. Service runs year-round but heavy weather disrupts it. In winter, several island businesses close entirely and the boats are carrying residents, not visitors.

For what to do on the mainland side between crossings, see our guides to things to do in Portland and the wider set of Maine islands beyond Casco Bay.

Frequently asked questions

What islands does Casco Bay Lines go to?

Peaks Island, Little Diamond, Great Diamond, Long Island, Chebeague Island and Cliff Island, all from the terminal on Commercial Street in Portland. Peaks gets the most frequent service and is the usual choice for a half-day trip. Bailey Island and Orrs Island are also in Casco Bay but are reached by road through Harpswell, not by ferry.

How long is the ferry from Portland to Peaks Island?

About twenty minutes each way, on the most frequent route in the system. Boats run year-round with a denser schedule in the morning and late afternoon to serve island commuters, and a thinner one in the middle of the day. Summer weekend departures fill, so arrive with time to queue rather than assuming you will walk straight on.

Is the Casco Bay Lines mailboat run worth it?

Yes, if you want to see the bay rather than stand on one island. The route calls at several islands in turn while you stay aboard, and it passes working lobster boats, ferry landings and Fort Gorges on its ledge. It is not narrated and the outside deck is cold when the wind is up — dress for the water, not for Portland.

Can you take a car to the Casco Bay islands?

On some runs, with a reservation, and it costs considerably more than a walk-on fare. Almost no visitor needs to. The islands served by ferry are small enough to walk or cycle, roads are narrow and residential, and parking on the islands is scarce. Bring a bicycle instead — it is carried for a modest fee and it makes Peaks, Long and Chebeague far easier to see.