The Irish squad's plane touched down on Tuesday evening just before 1700 BST.
Later, Mick McCarthy and the Irish players received a rapturous reception from a crowd estimated at around 100,000 people when they attended a welcome home party at the Phoenix Park.
The Irish manager said he had never imagined that such a large crowd would turn out to greet the squad.
"We had great support in Japan and the support here tonight is just incredible," said McCarthy.
It's great that our supporters want to welcome us back
Earlier at Dublin Airport, Mick McCarthy had said that while disappointed at Ireland's defeat by Spain, he was "glad to be back".
"We're still disappointed because we feel we should be still in the tournament," said McCarthy.
"But once it was over, once we were out of the tournament, we were looking forward to getting home.
"France were knocked out early and went home to a bit of derision and there was a bit of trouble in Russia.
"It's great that our supporters want to welcome us back".
The Irish boss said he had been delighted by Korea's surprise quarter-final win over Italy earlier in the day.
"I wish Japan had won as well because they both have been such wonderful hosts," added McCarthy.
We should all be very proud of our squad
Irish prime minister Bertie Ahern
The manager and his players met their families before arriving at the Phoenix Park at around 1800 BST when they were greeted by Irish President Mary McAleese and Prime Minister Bertie Ahern.
Northern Ireland's Deputy First Minister Mark Durkan was also present as a guest of Mr Ahern to congratulate the squad.
The team topped the bill at a special concert in the park, which also featured pop band Westlife.
Some fans had put pressure on the Irish Government to have the team parade through Dublin city centre in an open-top bus.
But safety fears meant that those plans were a non-starter.
Thousands packed the streets of Dublin when the team came home from Italia 90 but many people, including the then manager Jack Charlton, expressed concerns afterwards.
The park option for the welcome home was endorsed by Irish Prime Minister Bertie Ahern.
He agreed that a city centre procession might have generated a better atmosphere, but said safety issues had made that impossible.
"In the park, it is controllable and there is a vast amount of space. It is far safer for everyone," he said.
"I hope enormous crowds come out - the team deserves that. And I think they will.
"We should all be very proud of our squad."