DUBLIN — When Brendan Hall made the trip with three friends from Scotland to Dublin to check out the pep rally that Boston College was putting on a day ahead of the Aer Lingus Classic against Georgia Tech, they had no idea what to expect.

They had ties to both schools. Hall had family in Boston. One of his friends, Fraser Proud, spent a semester at Georgia Tech. They figured they’d take the hourlong flight and make a weekend of it — hit the pep rally and a rugby game on Friday, then see some American football on Saturday.

They didn’t necessarily know what all came with a pep rally, but they were counting on one thing.

“I expected there to be cheerleaders,’’ Hall said.

Niall Alexander, one of the friends in the group, said, “I’ve seen stuff like this on the TV, but I’m not too sure what happens and stuff.’’

They found themselves engulfed in a sea of maroon and gold in the heart of the Trinity College campus with the band blaring the Eagles’ fight song, coach Steve Addazio breathing pregame fire at the fanbase, and the four team captains practicing their touchdown celebrations.

Alexander acknowledged it was a bigger spectacle than television let on.

“You see the squads, the football teams, and it’s actually just so big, the squad size,’’ he said. “It’s definitely the sort of thing that you don’t get over here. So it’s really quite a good culture thing to see that way of doing things before a game. The build up.’’

In 1988, Boston College played the first game of American college football that Ireland had ever seen when they beat Army, 38-24, in the Emerald Isle Classic.Now football’s grown into a cultural force in America, and is a large attraction globally.

“I think it’s really cool,’’ Hall said. “We’re all fans of American football. It’s good that it’s coming over to Europe so we get to see games live, that’s really cool.’’

“I’ve never been to a game before,’’ Alexander said. “It’s the best chance we’ll get without going to America.’’

There’s still no question about which sports the Irish cling to most.

“Rugby and soccer are more popular,’’ Hall said. “But American football’s definitely gaining popularity, which is really cool.’’

“It’s definitely on the up,’’ Alexander said. “I didn’t really realize it was actually so popular till I went to university and saw a couple other guys like it as well. It’s still not one of the big sports, but it’s definitely on the up. It’s nowhere near [soccer], but probably maybe a little bit less than rugby over here.’’

Laoise and Clíona McMahon, twin sisters who attend Holy Faith Secondary School in Clontarf, heard the buzz about American football in Ireland two years ago when Penn State played Central Florida in the Croke Park Classic. When they heard that college football would be returning this year, they made sure to find a way to get into Aviva Stadium on Saturday, both getting gigs selling programs.

“We’re just more aware of it,’’ Clíona said. “When they came around this year, we were like, ‘Yeah, we want to work at this game so we can go in and see it.’ ’’

The sport’s still something of a mystery.

“I’ve never seen an American football match in my life,’’ Laoise said.

But it’s an intriguing one.

“I know very little about it,’’ Clíona said.

Both sisters play Gaelic football, a game an American once described to them as “People hitting balls with a giant spoon.’’ But they have a mutual appreciation that crosses both sports.

It was also on the to-do list for some of their classmates.

“I know people in my year will be like, ‘Oh, that’s a really cool game to go to,’’ Laoise said. “Some of my friends were looking for tickets. So it’ll be a very interesting and different experience. It’s not here often.’’

At a cafe in the middle of the Temple Bar district, BC and Georgia Tech pennants hung as decorations while passersby popped in and out for food and drinks.

Mark Jordan has been the manager at Bad Ass Cafe for four years. He was there when Notre Dame had the city buzzing for the Emerald Isle Classic in 2012, when 48,820 filled Aviva Stadium. Two years ago, when Penn State played Navy in the Croke Park Classic before 53,304, the city was just as vibrant, packed with locals and out-of-towners.

“Around here, it’s different,’’ Jordan said. “It’s really touristy around here in this area. But a lot of the Irish are into the American football as well. So it can be big. It can be high profile for the weekend. High profile.’’

It has an obvious trickle down on the cash registers, Jordan said.

“Very good for business,’’ Jordan said. “It’s not just the one or two days. People are coming for a week. So you get a few days before, obviously Saturday will be busy the day of the game, but then Sunday, Monday, Tuesday, people will be still around. They make a week out of it, so it’s good.’’

One of the people was Rich Oliver, 70, who made the trip from Georgia to spend a weeklong vacation with his wife in Ireland. Oliver and his wife first visited Dublin in 1999 and fell in love with the city.

“We’ve always been looking for an excuse to come back,’’ said Oliver. “When they announced the game, we said ‘we’re in’ right away.’’

They got to Ireland Monday to give themselves a chance to take in as much of the culture as they could. They took tours of the West Coast — “very different than it is in Dublin’’ — exploring the seacoast and islands and some of the smaller towns.

They peeked in on Boston College’s pep rally Friday afternoon before the Yellow Jackets swarmed Trinity College’s courtyard later in the evening.

“I think it’s great because you’re almost like ambassadors coming over here,’’ Oliver said. “But the Irish people are so unbelievably friendly and interested and everything and I think for the players, probably an opportunity of a lifetime.’’

►BC braces for Tech offense, Page 6

Julian Benbow can be reached at jbenbow@globe.com. Follow him on Twitter @julianbenbow.