The mainly Portuguese visitors began arriving on chartered flights this morning, with at least 10,000 set to leave again tonight.
Garda resources were stretched to their limit as officers tried to oversee the massive logistical operation, while also protecting Queen Elizabeth.
Close to 50,000 people are expected to pack into the Aviva Stadium – renamed the Dublin Arena for tonight – for the game between FC Porto and their near neighbours Sporting Braga.
As the game clashes with the queen’s visit, extra security measures have been put in place and many of the travelling fans will be disappointed that Dublin is under lockdown.
Dublin Aiport was prepared for one of its busiest days on record as more than than 60 extra flights arrived.
“We have been working on this for over a year now,” Dublin Airport Authority spokeswoman Siobhan Moore told the Herald. “We’ve worked with Uefa, our own FAI, Dublin City Council and the gardai.”
The airport handles an average 450 flights a day but the extra flights still won’t make it the busiest day – that was in July 2006, when it handled 91,000 passengers.
There is a Uefa requirement that the fans be segregated arriving and departing the airport, although there is no history of animosity between the clubs.
The numbers coming from Braga, the smaller club, are less than originally thought with some tickets likely to be snapped up by Dublin fans.
Around 85pc of the fans arrived between 9am and 1pm, but the departure is the hardest element of the plan to cope with, the DAA said.
The losing team will be first to depart for the airport, with the winning team’s fans following about 45 minutes later from the ground.
Parking the 60 or more aircraft on the airfield presents its own problems, but the plan is to get most of the departing aircraft out between midnight and 4am.
The Irish Aviation Authority said the extra aircraft numbers “would not be particularly problematic” for air traffic controllers.
“Our numbers (of aircraft) are down so we would have had that number at its peak over the years,” Lillian Cassin said.
The air space restrictions over Dublin will not rule out out the traditional helicopter camera “beauty shot” of the Aviva Stadium at the opening of the Braga versus Porto clash.
“All agencies are working together to ensure the success of both the State visits,” Ms Cassin said.
“While there are operational issues associated with both, none of these issues is insurmountable,” she added.