*Please note, due to COVID-19, Casco Bay Lines is operating with reduced service until further notice. The current reduced schedule can be found here.  Additional information related to the schedule and CBITD’s operations during COVID-19 can be found here and should be reviewed before visiting our terminal or traveling on our vessels. Please be aware that operations of businesses on the islands may also be impacted by COVID-19 and CBITD recommends contacting your destination before traveling.

Approximate travel time from Portland: 20-25 minutes one-way (trip times vary based upon cargo volume)

Great Diamond Island is an island in Casco Bay, Maine. It is part of the city of Portland, Maine.

The island is not easily accessible by motor vehicle and has a limited network of roads. The primary modes of transportation are golf carts and bicycles. This fact has become a selling point for the island, marketing the area as “car free” and “kid friendly.”

Ferry Schedule

Things to Do on the Island

Diamond Cove is a ferry stop at the northeastern side of the island. The Diamond Cove properties are on the grounds of the former Fort McKinley, making use of the army barracks and officer’s quarters as renovated homes. The abandoned concrete coastal artillery batteries still exist in the woods at the east of the island, although they are technically private property and off-limits due to safety concerns.

The community is gated and, for the most part, not open to the general public, although the Diamond’s Edge restaurant is open and located just off the Casco Bay ferry dock. Tours of the grounds, by reservation, are also available. A limited number of homes have also been built on the waterfront areas of the island; many have been featured in local magazines and newspapers.