Calendar Islands, Maine: Beyond the 365 Myth to the Shores You Can Visit
Ask about the Calendar Islands, Maine, and someone on the Portland waterfront will tell you Casco Bay holds one island for every day of the year. It makes a good story on a ferry deck. The count is closer to 785 islands and ledges, and a handful of them, led by Peaks, Great Diamond, Chebeague, Long, Cliff, and Jewell, make the best summer day trips from Portland.
The number matters less than knowing which shores you can walk on. Some islands are busy little towns with cafés and museums. Others are private communities where you stay on the road or the beach. A few have no ferry at all and need a small boat and a good tide.
So the useful way to read the bay is by island, by access, and by the time you have. The islands below are sorted that way, with the ride between them treated as part of the trip.
Why Are They Called the Calendar Islands?
The name comes from an old boast, not a survey. In 1700, a British military engineer, Colonel Wolfgang Romer, inspected the coast and reported "as many islands as there are days in the year" in Casco Bay. The line stuck, and the islands became the Calendar Islands.
Long before that, this bay was the homeland of Wabanaki people, including the Abenaki. On Great Diamond Island, archaeological evidence shows the island was used for hunting, for gathering food near shore, and as a base for fishing offshore. The English name is only a few hundred years old. The human story on these islands is much older.
Is There Really One Island for Every Day of the Year?
No, there are more. Friends of Casco Bay counts 785 islands and exposed ledges in the bay. Many are bare rock that vanishes at high tide. Some are home to seals, gulls, and cormorants, not people.
So the "365" number undersells the bay in one way and oversells it in another. There are more islands than days. But only a small share have docks, public trails, or beaches you can visit. That gap between the legend and real access is what trips up first-time visitors.
Here is a simple way to sort them:
Ferry islands with towns: Peaks, Great Diamond, Little Diamond, Long, Chebeague, and Cliff.
Protected or wild islands: places like Jewell Island and The Goslings, where land trusts or the state protect the shore.
Private islands and ledges: most of the rest, best enjoyed from the water.
Where Does Casco Bay Begin and End?
Casco Bay runs from Two Lights in Cape Elizabeth to Cape Small in Phippsburg. Halfway Rock Light sits near the middle of that line, which is how it got its name. Past it lies the open Gulf of Maine.
Inside that line, the bay covers about 229 square miles of water and 578 miles of shoreline. Portland sits near the southern end, so most day trips stay in the lower and middle bay. The shoreline is changing too. Island groups are now working with Portland and grants from the Casco Bay Estuary Partnership to slow bluff erosion on Peaks, Long, Chebeague, and the Diamonds.
Which Islands Are Worth Your Time?
The best island for you depends on one thing: do you want a town, a trail, or a beach with nobody on it? Each of the islands below answers that question in its own way. Pick by what your group wants to do once your feet hit the sand.
Peaks Island for an Easy First Visit
Peaks is the easiest island to visit from Portland. The ferry ride takes about 20 minutes, and you step off right into a small town. It is the most populated island in the bay, with more than 900 people living there year-round.
Once ashore, you have a lot within walking or biking distance:
Fifth Maine Regiment Museum, a Civil War memorial hall near the shore.
Umbrella Cover Museum, a quirky spot on Island Avenue with seasonal hours.
Battery Steele, a big World War II gun battery hidden in the woods.
The rocky back shore, where the open ocean hits the island.
Back in the late 1800s, Peaks was called the Coney Island of Maine, with a theater and hotels. Most of that is gone now.
Great Diamond and Little Diamond for Different Kinds of Stops
These two sit side by side, but they feel very different. Great Diamond has Fort McKinley, built in the 1890s to guard Portland Harbor. Its old barracks now hold homes and the Inn at Diamond Cove. The fort museum has operated by reservation only, so check ahead.
Know this before you go: much of the old fort land is private, and parts of it are open only on arranged tours. Great Diamond also has trails, picnic spots, and a restaurant near the marina at Diamond Cove, with seasonal hours. The ferry takes 25 to 30 minutes, and not every run stops at Diamond Cove, so check which dock you need.
Little Diamond is mostly a private summer community. It was called Little Hog Island in colonial times. Treat it as a pretty place to see from the water or a quick stop if you have a rental there.
Chebeague, Long, and Cliff for a Slower Day
These three reward people who like quiet roads more than gift shops. Chebeague is one of the largest islands in the bay, almost five miles long. It has about 360 year-round residents and the Great Chebeague Golf Club. Its name is said to mean "isle of many springs."
Long Island is about three miles long and one mile wide. It is best seen by bike, so bring your own. Visitors find Sandy Beach, known for sand that squeaks underfoot, plus a library and a few seasonal businesses. It left Portland to become its own town in 1993, and Chebeague followed in 2007.
Cliff Island is the smallest year-round island and the last ferry stop down the bay. It is shaped like an "H" and has only unpaved roads. People walk, bike, or use golf carts. A lot of its land is protected, so it feels rural and slow.
Jewell Island and Other Less-Visited Shores
Jewell Island is the one people picture when they hear "secluded Maine island." It sits in the outer bay with no ferry service. You need your own small boat or a charter to get there, and whether you can land depends on the tide and the weather that day. Visitors come for its woods, trails, and rocky shore on the edge of open water.
Other quieter shores include the Goslings, a pair of small islands with a protected preserve, plus beaches like Sand Island and Vail Island. These spots feel wild because so few people can reach them. If a beach all to yourselves sounds right, read about a private beach by boat.
What Can You See Between Island Stops?
The ride between islands is half the fun. Heading out of Portland, you pass Fort Gorges, a granite fort on a ledge in the harbor. You can learn more about a Fort Gorges boat tour and what is inside.
Toward the harbor mouth, Portland Head Light stands on the cliffs of Cape Elizabeth. It was first lit in 1791, and from the water you see the full cliff and tower at once.
Whitehead Passage, between Peaks and Cushing Island, is a narrow run with steep rock walls. Harbor seals haul out on the ledges nearby, and ospreys fish overhead, though sightings are never guaranteed.
How Do You Reach the Islands from Portland?
You have two good ways out: the public ferry or a private boat. The ferry is cheap, runs all year, and serves the town islands well. A private boat reaches the wild shores and lets you visit several islands in one outing.
Calendar Islands Maine Visitors Can Reach by Ferry
The Casco Bay Lines ferry leaves from its terminal on Portland's waterfront. It serves Peaks, Little Diamond, Great Diamond, Long, Chebeague, and Cliff. It runs every day of the year, carrying people, mail, and freight.
Schedules change with the seasons. As of fall 2026, the fall ferry schedule runs September 8 to October 12, 2026. The winter schedule starts October 13 and runs to May 20, 2027. Winter means fewer trips, so plan return times with care.
Travel times vary a lot. Peaks is about 20 minutes. Chebeague is over an hour from Portland, since the ferry stops at other islands on the way. Many Chebeague visitors take a separate 15-minute boat from Cousins Island in Yarmouth.
When Does a Private Boat Make More Sense?
A private boat makes sense when your list includes places the ferry skips. That covers Jewell Island, Fort Gorges, and beach drops at spots like South Beach or Sand Island. It also helps when you want two or three islands in one day without waiting at docks.
A boat gets you to the shore, but it does not give you permission to land. Each stop still depends on who owns the shore, whether landing is allowed, and whether the tide and swell make it safe that day.
Our standard private charters run $175 per hour for up to six guests, with trips starting at two hours. For simple point-to-point trips, our water taxi rates list Peaks at $65, Great Diamond at $65, and Jewell Island beach drops at $200.
Which Shores Need an Access Check Before You Go?
Many shores look open from the water but belong to someone. Little Diamond is mostly private. Much of the Fort McKinley land on Great Diamond is private too. Rule of thumb: stick to public beaches, roads, and posted preserves.
Groups like Maine Coast Heritage Trust and Oceanside Conservation Trust of Casco Bay protect several islands. The Maine Island Trail Association (MITA) works with owners to open some wild islands to careful visitors. Rules differ from island to island. Some preserves limit fires, dogs, or camping.
Before you land somewhere new, check these points:
Who owns the land, and is it open to visitors?
Are dogs allowed, and must they be leashed?
Is there a safe landing at the tide you will arrive?
Is there a bathroom? Most wild islands have none.
What Should You Plan Before an Island Day?
Plan around time, tide, and weather first. The island choice comes next. A good plan leaves room for the bay to change its mind.
How Much Time Do You Need on the Water and Ashore?
A single island by ferry fits in half a day. Peaks works well in three or four hours, including a walk to the back shore and ice cream. Chebeague or Cliff needs a full day, since the ride alone eats up time.
On a private trip, three hours is a common choice. That covers the harbor forts, Portland Head Light, and one short landing. Four to six hours lets you add a beach drop or a longer walk ashore. Trips can run up to eight hours if you want to go island hopping.
For ideas on pacing a longer day, see our tips on island hopping in Casco Bay.
What Changes with Weather, Tides, and Seasonal Hours?
Fog is the big one in summer. On many mornings, fog sits on the bay and lifts by midday. Wind picks up in the afternoon, which makes the outer islands choppier. Tides here rise and fall several feet, which can cover a beach or strand a landing spot.
We watch the forecast and do not go out in unsafe conditions. If weather cancels a trip, you can get a full refund or reschedule. Our charter FAQ page covers more of these details.
Hours shift ashore too. The Umbrella Cover Museum keeps seasonal hours. The Fort McKinley Museum has worked by reservation. After Columbus Day, many island cafés cut back.
What Should Families Bring?
Bring layers even in July. The water stays cold, and the air on the bay can feel 10 degrees cooler than downtown. A windbreaker, hats, and sunscreen cover most days.
For a private trip, pack snacks and drinks in plastic or cans. Glass and red wine stay off the boat. There is no bathroom aboard, so use the private bathrooms at Fore Points Marina before you go. Share kids' ages and weights ahead of time so the right life jackets are ready. Calm dogs are welcome with notice.
Kids love spotting harbor seals, but keep a respectful distance. NOAA advises staying 50 yards from seals. Many families end the day with a Maine lobster roll back in Portland.
Frequently Asked Questions
How Many Islands Are in Casco Bay?
Casco Bay has about 785 islands and exposed ledges. Many are small rocks that flood at high tide. Only a handful have year-round towns and ferry service.
Which Calendar Island Is Easiest to Visit from Portland?
Peaks Island is the easiest to visit. The Casco Bay Lines ferry gets there in about 20 minutes, and shops, museums, and a beach sit close to the dock.
Can You Visit More Than One Casco Bay Island in a Day?
Yes, you can. By ferry, pairing nearby islands like Peaks and Great Diamond takes careful timing. A private boat makes it easier, since you leave each island when you are ready.
Do You Need a Private Boat to Visit Jewell Island?
Yes, you need your own boat or a charter. No public ferry serves Jewell Island. Landing depends on tide and weather, so trips there need some planning.
Can You Land on Any Island in Casco Bay?
No, many islands and shores are private. Stick to public beaches, town roads, and posted preserves. When unsure, ask your captain or check with the land trust that manages the island.
Choose the Island, Then Choose the Boat Ride
The 365 legend is fun, but you only need one or two islands to have a great day. Start with what your group wants: a town to wander, a fort to explore, or a beach where nobody else is around. Then match the ride to it.
Peaks, the Diamonds, and Long work well by ferry. Jewell, Fort Gorges, and the quiet beaches need a small boat and a landing plan that fits the tide.
If your list leans toward the wild side of the bay, look over Bird's Eye Maine private tours and call Captain Matt at 207-632-9369. Name the islands on your list, and he will tell you which ones fit the tide and the hours you have.
