Special Activities: This is a free ferry ride to either (or both) of the two most popular Boston Harbor Islands – Georges Island (with historic Fort Warren, Plays in the Park, and ranger-guided tours) and Spectacle Island (with a life-guard supervised beach and 5 miles of hiking trails).  Free tickets for the Boston Harbor Cruises ferry will be distributed on a first come, first serve basis at Long Wharf-North, 66 Long Wharf, in downtown Boston (near the Aquarium subway station) and Christopher Columbus Park.  The ticket window will open at 7:00 a.m. The ferry leaves every 30 minutes starting at 8:00 am, with a 3-4 hour window to return (depending on which island).  Each adult in line may pick up a maximum of 4 tickets.  (There will be no special arrangements for groups of more than 4 to be on the same ferry).  Tickets will be handed out for the earliest ferry, then the next, and so on, until all ferry seats for the day are distributed.

http://highlandstreet.org/august-7-additional-information