One of the funniest events at the Belfast Harbor Fest has to be the Cardboard Boat Race. Taking place along the waterfront during the festival from August 7–9, 2026, the race is exactly what it sounds like, teams build boats almost entirely out of cardboard and then attempt to paddle them across the harbor. It turns the race into more than just a competition, it becomes a fun display of imagination and teamwork. Even when a boat sinks, the crowd usually cheers the loudest because those moments are often the most memorable. For spectators, the Cardboard Boat Race is one of the highlights of the Belfast Harbor Fest.