So much to do in the Bar Harbor Acadia area. Here's some ideas :

Acadia National Park
Swimming, beachcombing, kayaking, hiking, cycling, rock climbing, walking, site-seeing. Visit the Park Information Centers to get all the details and locations. The sunrise on top of Cadillac Mountain is especially nice, as it’s the first place it can be seen in the U.S., as well as Schoodic Point, northwest of Hancock off Rt. 1. Check out the Natural History Museum at Sieur De Mont Springs, and Tea and Popovers at the historical Jordan Pond House.

Carriage Trails
(Walking and Cycling Paths)
There are many carriage roads all over the Island, built during the Depression and earlier. Many are in Acadia National Park, but some can be found off of the main highways. You can access a few carriage roads in Northeast Harbor and Seal Harbor, including Little Long Pond and Day Mountain, in Seal Harbor.

Mountain Hikes
Mountains trails that can be accessed outside of the Park include: Door Mountain, Day Mountain, Eagle’s Craig, Parkman, Saint Savior.

Maine Coastal Islands National Wildlife Refuge
(formerly Petit Manan Wildlife Refuge)
A 1900-acre wildlife refuge with walking trails northeast of Hancock. http://www.fws.gov/northeast/mainecoastal/

Swimming
Great swimming lakes include Echo Lake, Long Pond, Beech Hill Pond

Gardens
Asticou and Azalea Gardens in Northeast Harbor are beautiful, as well as Sieur De Mont Springs in Bar Harbor.

Beaches (sandy)
Try Sand Beach in Acadia National Park and Seal Harbor Beach in Seal Harbor, as well as the State Park beach in Lamoine. There's also a wonderful lake beach at Echo Lake.

Golfing
Kebo Valley Golf (Bar Harbor); Northeast Harbor Golf; Causeway Golf Club (Southwest Harbor); Bar Harbor Golf Course (Trenton, off Island); White Birches (Rt. 1, Ellsworth)

Tennis
Northeast Harbor municipal courts (near the town pier); Bar Harbor municipal courts; MDI High School Courts (summer only); Hancock Point tennis (you must pay around $25 to become a member)

Biking
There are several bicycle rental shops in the commercial district of Bar Harbor. Mountain biking is great at Eagle Lake, and other spots in Acadia

Bar Harbor Bicycle Shop: (207) 288-3886
Cadillac's the North Face:  (207) 288-9600
Acadia Corporation - Acadia Outdoors: (207) 288-2422
Southwest Cycle: (207) 244-585; (800) 244-5856 (toll-free)
Free-Ride Scooters: Bar Harbor; 207-669-4139; info@freeridescooters.com

Canoeing/Kayaking
Eagle Lake; Echo Lake; Long Pond; and in Bar Harbor! Canoe rentals are available at the lakes, at the head of the Island, and in-town Bar Harbor (see below for rental and tour information)

National Park Canoe & Kayak Rentals, Mount Desert:  (207) 244-5854
Acadia Outfitters Kayak Rentals and Tours, Bar Harbor:  (207) 288-8118
Maine State Sea Kayak: (207) 244-9500
Coastal Kayaking Tours Inc, Bar Harbor: (207) 288-9605
National Park Sea Kayak Tours, Bar Harbor: (207) 0342
Acadia Outfitters Kayak Rentals and Tours, Bar Harbor: (207) 288-8118
Hancock Point Kayak Tours: (207) 422-6854

Local Theater
Acadia Repertory Theater in Somesville
Dinner theater at the Deck House restaurant in Southwest Harbor.

Misc.
Whale Watch boat trips
Deep Sea Fishing
Scooter Rides
Day cruise to Nova Scotia on the “CAT” ferry
Ferry to Great Cranberry Island (Northeast Harbor)
Horseback riding in Hancock, horse/carriage rides in Seal Harbor (in Acadia National Park)