Boston’s FIFA Fan Festival opened Friday at City Hall Plaza, but the first two days were already gone before the gates opened. Fans hoping to walk up for Friday or Saturday were told to look elsewhere to watch the World Cup, as the plaza’s opening weekend filled fast.

The demand is striking even by World Cup standards. Mike Loynd said nearly 150,000 fans had already registered for the festival, which is limited to 5,000 people at any one time. Registration lets fans choose the day or match they want, but it does not guarantee entry if the plaza hits capacity, and children under 18 need a parent or guardian waiver. That is why officials are steering people toward planning ahead rather than showing up and hoping for a spot.

Boston Mayor Michelle Wu said her office helped secure over 500 free tickets for community members, especially children and their families, and urged fans to keep trying for the other 14 days through June 27. She also asked people to make a plan, arrive with the city’s pedestrian traffic in mind, and register online in advance if they want to attend Fan Fest. Wu said, “Soccer belongs to the people,” but she also made clear that capacity rules will control access once the plaza fills.

The festival is set to run with live broadcasts of two to three matches a day, musical performances, a curated cultural showcase and local food vendors, while the Wu administration sponsors community watch parties in Dorchester, East Boston and at the Parkman Bandstand on Boston Common. At least 500 city residents will head to Foxboro to watch games live at Gillette Stadium, which is being rebranded as Boston Stadium for the tournament, including viewers for the Scotland game, the first men's World Cup match in 28 years begins in Boston Stadium. Parking restrictions are also in effect for all events.

The sharpest friction is between the invitation and the limits. Martha Sheridan said the festival would be the “epicenter of Boston soccer football for the next 16 days,” and the city is building out that idea with fan walks planned Saturday and Sunday for Haiti fans and the Tartan Army around City Hall Plaza. But the event’s real shape will be set by the 5,000-person cap: the festival can welcome crowds, yet it can only admit a fraction of the nearly 150,000 people who have already registered.