Boston Harbor Cruises leaves from Long Wharf, between the Aquarium and the Marriot Long Wharf Hotel. We took the sunset cruise, leaving at 7 pm and returning at 830. It was absolutely beautiful, and the kids loved it. There is a snack bar on board, and sparkling clean restrooms. Definately bring a sweatshirt-we were freezing! To make a day of it, go to the aquarium first, or the 3D theater, and have dinner across the street at Fanieul Hall. Or go on one of the cruises that are earlier in the day, then have cocktails at Tia's, in the Marriot Long Wharf.