Located at the northern end of Great Diamond Island, our 43 slip deep-water marina can accommodate vessels up to 110+ ft. Our private marina is available exclusively for guests at Diamond's Edge Restaurant, the Inn at the Diamond Cove, and all overnight boaters.
Visit the island to explore and take in 193 acres of spectacular natural landscape that inspires outdoor recreation and relaxation. The island is home to Diamond Cove, a small residential community that was a former military base built during America's Gilded age, the luxurious Inn at Diamond Cove, the highly-rated Diamond Edge Restaurant, and the Fort McKinley Museum.
All slip reservations include complimentary water and Wi-Fi, and access to shower and bathroom facilities. Please hail us on VHF channel 09 as you enter the harbor and we'll happily guide you to your slip. All dockage reservations will be processed through Dockwa.
We invite boaters to dock and dine at our newly renovated Diamond's Edge Restaurant featuring fresh, local New England favorites.
If arriving by boat to dine at the restaurant, please book online via Dockwa and make note of your reservation time during checkout.
The facility, the people, the beauty - all outstanding. Couldn't ask for anything better. Chris was outstanding and sooo helpful. Goes above and beyond to accommodate you....
Nice place and a great dinner.
great people, the island is beautiful, views amazing and its so peaceful .The Ferry or water taxi options are great for Portland.
The marina crew was very friendly and dinner was awesome.
Great marina and dock master is great!
Great marina and location for visiting GDI. Chris the manager and all other staff were helpful and a pleasure to talk with. Can’t wait to go back.
Chris, the Dockmaster was very helpful and friendly. We ate at the Diamond's Edge Restaurant and the food and drinks were excellent. Very positive experience.
The dockmaster, Chris, made us feel very welcome and his crew were very helpful. Great dining experience at the Crown Jewell nearby. Nice trails for walking.
Great service at the marina and great service at the restaurant. The drinks were tasteless and the food was 3 stars at best. Next time we will bring food and grill on the boat.....
All around great place. People having fun.
Actually, 4.5 stars. Lovely, lovely spot on this earth, like no other. Not 5 only because not well set up for the cruiser crowd....no W/D, showers a bit of a hike. Dockmaster Chris quite helpful and friendly, restaurant 4.7. Will definitely be back.
Diamond's Edge is an incredible stop. The island itself combined with the hospitality makes it a real gem and a stop we like to make at least once every year.
Three friends and I dined at Diamond's Edge this past Friday night. The dockmaster was exceptionally helpful and friendly. The dining experience - on the lawn - was fantastic from start to finish. Highly recommend Diamond's Edge to all my friends.
Chris on the dock was the best and more than helpful. Restaurant soo much better than last time which was before Covid. The walking map very helpful in understanding where the permitted places were to walk. Street names would be helpful on the map. The lady at the inn fixing our bagel breakfast could not have been nicer. She made our morning. Good job to all.
As always, this is one of the most pleasant marinas to pull into. They're always waiting for you to arrive and ready to help you dock. And it's such a beautiful location with great food and fun beaches! Update: A year later, another visit, and another great experience. The marina manager always makes the process so easy, and it is such a great location.
We love coming in to Diamond Island. It is one of our favorite trips. Chris, the Dockmaster, is always accommodating. It is always a great dining experience at the Inn restaurant, and enjoy the amenities at the hotel.
Amazing, secluded little spot. Food and drinks at Diamonds Edge restaurant are phenomenal. The dock master Chris is friendly, helpful and accommodating. The inn is beautiful and we’ll probably stay a night or two next year to break up a long boat vacation. My only complaint is there is limited hot water if someone is in both the men’s and women’s showers. You might end up running out so best to put some time between showers.
Great small marina with two good restaurants a short walk away. Note-No WIFI or cell service. Chris Johnson, the dock manager, is the best!!
Chris and his team were very helpful/responsive in getting us situated on the island. Thanks for a great experience.
This location is absolutely beautiful. Small protected cove, very close to Portland. The amenities are limited...no wifi, spotty cell service, bathrooms are quite a long walk. The residents of the island do not want marina guests to walk around. You are required to request a golf cart ride up to the Inn to use the pool. Chris is a very pleasant and customer service oriented manager. He does a great job! Also, skip the Diamond's Edge restaurant and eat at Crown Jewel instead where the food outstanding!
Wonderful help on and off the dock.
Great stay and Chris the Dock Master was outstanding. Very accommodating and very customer focused.
Chris and John are excellent at their craft. Very helpful. Really enjoyed the comings and goings of the ferry.
Diamond’s Edge Marina was amazing! Dockwa calculating the wrong dockage fee was our only issue.
The dock manager was very helpful and friendly. They are a little short handed, but everything seemed to get done and I got all the help I needed.
The dock master was rude and offensive. He asked us to tip the dock hand which we already had done. He then came to our table to confirmation our reservation which we did online. He again asked us to tip the dock hand. When we returned to our boat, he asked us again about tipping the dock hand. He was pleasant enough, but was extremely rude and intrusive by constantly chasing us down for the fee for stopping at the dock and tipping the dock hand. Unfortunately, I will not return there because of him. I guess the $250 lunch isn’t good enough.