When Vicky Britton and Ryan Hickey, two graduate exchange students in Boston University’s College of Communication, presented their passports to order alcoholic drinks at Regina Pizzeria in Allston, the staff rejected their IDs.

“We asked to speak to the manager, and the manager said, ‘We can only take U.S. passports, we have to crack down on this,’” Britton said.

Hickey said passports are the only means of identification available to him and Britton as exchange students from Ireland.

“Our passports are the only way we can get drinks in Boston,” he said.

Bay State restaurants with liquor licenses can choose their own method of checking identification before selling alcohol, according to the Massachusetts Alcoholic Beverages Control Commission.

Licensees may adopt a “conservative” policy and can choose to use any of four types of identification that, if valid, could protect them from possible charges, according to the ABCC.

These include a state driver’s license, a state liquor identification card, a passport and a military identification card.

“If you have any concerns whatsoever you are allowed to refuse service of alcohol, because no one is damaged by not being served alcohol,” said Stuart Thompson, senior partner of East Coast Associates and former president of the Massachusetts Restaurant Association. “The only exception would be if you were doing it for discriminatory purposes.”

Other local restaurants said they have put this law into effect before.

“We have a similar policy,” said Amanda Carbone, manager of Sunset Cantina. “By law for Massachusetts, we only have to accept a U.S. passport or Massachusetts license.”

However, she said, this is an issue that does not arise too often.

Carbone said Sunset Cantina refuses an ID about once a month.

“A lot of people who know that they’re going to be here for a while get other identification,” she said.

But for other restaurants, this is not an issue at all.

“If [the ID] looks fake, I would [refuse service], but otherwise I would serve them,” said Irene Barone, owner or Carlo’s Cucina Italiana in Allston. “If they don’t have any other ID, how can you refuse them?”

Thompson said although identification can be questionable, the law has become more lenient.

“It wasn’t that long ago in the Commonwealth of Massachusetts that you could only use a Massachusetts license,” Thompson said. “With the large student population and international travelers they have expanded. But if you have any question about the validity, you are allowed to not accept the identification.”

Britton, however, said she has never faced this issue in the past.

“This is the first time it happened to me,” she said. “I find it shocking in this day and age that people won’t take an international passport.”

COM graduate student Christine Breslin, who was with Hickey and Britton, said the group of friends found it strange because no real explanation was given.

“They didn’t seem to give a real perspective or laws to back it up,” Breslin, an exchange student from Ireland, said. “‘This is what it is’ was basically their attitude towards us.”

Regina Pizzeria declined to comment on the situation.

However, Thompson said the pizzeria made the right choice by playing it safe.

“Unless it’s a discriminatory thing, the server has a right to do it,” he said. “The servers are told, ‘If you’re not sure, don’t do it.’”