Seeking or providing an abortion in Ireland is currently a criminal offense that carries up to 14 years behind bars but that may change. A "yes" vote repeals the 8th Amendment in the country's Constitution, an amendment that equates the life of the mother and her unborn child.
If repealed, abortion can then be regulated as it is in both the United States and the United Kingdom. If overturned, lawmakers are expected to debate proposed legislation allowing abortions within the first 12 weeks of pregnancy, and after that in cases of fetal abnormalities or serious risks to the mother’s health.
A "no" vote keeps the 8th Amendment in place, banning abortions even in cases of rape, incest, fatal fetal abnormality and non-life-threatening risk to maternal health. The fight between the two sides has become vicious, which, in part, has motivated a lot of Irish voters to fly home.
"The initial spark was seeing how vitriolic and how nasty the other side became," Ause Abdelhaq-Braike, 23, told ABC News. Abdelhaq-Braike made the 12-hour journey from Nairobi to vote "yes" Friday.
Abdelhaq-Baike is not alone.
Irishmen and women have traveled back to their homeland from the U.S., Japan, Thailand, Sweden, Australia, and Costa Rica, to name a few, many posting on social media with the hashtag #HomeToVote.
The National Youth Council of Ireland estimates some 125,000 additional voters registered in the lead up to the vote by the cut off date of May 8.
The 8th Amendment was approved by 67 percent of voters back in 1983, which means no one under the 53 years old has voted on the issue -- until now.
"I hope history remembers us as the generation that finally drew a line in the sand," Abdelhaq-Braike said. "They'll say that we all stood together to finally eradicate a disgusting, backward law and take control of our own bodies. We finally did away with the religious guilt and shame that has been hanging over our country for centuries. We finally drew a line in the sand and said, 'enough is enough, the time is now.'"
Abdelhaq-Braike said he had no choice, he had to be a part of it.
"Abortions are happening. So, in any world where this is happening, we should be legislating," he added.
"We don't even know the statistics for the amount of women who put their lives at risk every year through self-induced abortions that happen with coat hangers or belly-flops or douching with Coca-Cola to instigate internal chemical burns," Abdelhaq-Braike explained.
"If I was confident it would pass, I wouldn't be so anxious to get home. The reason I'm going is because I think my vote will actually matter," he added. "The number flying home for this will be significant."
"I'd never forgive myself if I didn't go back and stand with Irish women," Eoin Byrne, 31, told ABC News.
He lives in Leeds, England, and says he'll be on Irish soil, ready to vote by 7:30 a.m. Friday.
"The basic rights to own one's own body have been taken away and this is the first time in my lifetime I'll have the chance to change that," he said.
"Conservative Ireland is not gone... The church still has a lot of sway no matter what anyone says but this is an opportunity to stand by our mothers, our sisters, and our friends," he said.
Byrne said his friends, sister, and everyone else seems to be talking about the vote.
"I have friends who have been out campaigning and also those who been having quiet, emotional conversations with family," he added.
"I am absolutely terrified," he said. "I don't know what kind of Ireland it will be Saturday."
For Sean O'Connor, the flight from Boston to Dublin hits close to home.
"I've had personal experience with women I care about that have had crisis pregnancies in Ireland and have seen first-hand the difficulties the 8th [Amendment] puts them under. I am hoping this vote will lead to compassionate legislation that will alleviate some of the misery the women of Ireland have to endure," he said.
"I am going back to vote to do my part to release the country from the long grip that the church and its moralizers have held it in," he told ABC News.
Toronto resident Rachel DeNógla, 28, flew back because she's "never felt more affected by a vote in Ireland" in her life.
"I hope to move back to an Ireland that lets me and any future daughters or granddaughters or nieces have a choice over our bodies and what happens to them," she said. "It’s not OK that women have died as a result of the 8th Amendment. And it’s not OK to ship our problems off to another country and ignore the reality."
She believes it's time Irish women get the treatment they deserve in the country.
"It's honestly about time Ireland opens its eyes and cops on and treats women the way they deserve to be treated," DeNógla said.
"It's my last chance in this generation to contribute to the well-being of my homeland," Tady Walsh, 42, told ABC News. He traveled back to Ireland from Brittany, France.
"I missed the marriage referendum, not knowing I could have voted," said Walsh, who didn't realize he was still a registered voter. "So I’m going home to vote because I can. And I’ll be voting 'yes,' as I’m a father to a daughter. I have sisters. I have female cousins. I have friends who are women. I have friends who have traveled to the U.K. for abortions. So I’m voting to give them choice because I trust them, I trust the women of Ireland."
"This is not a vote about abortion, regardless what the 'no' side peddles. It’s about [the] autonomy of choice. It’s about access to healthcare, it’s about respecting and supporting women to do what is needed for them. There is nothing in the constitution of Ireland that tells me, a man, what I can or can’t do with my body. Why should it be any different for women? So that’s why I’m going home to vote."
It will come down to the wire, according to latest polls.
The Irish Times/Ipsos MRBI opinion poll found that 44 percent of respondents said, "yes," and 32 percent said, "no," and 24 percent said they were either not sure or not voting. Those who have decided are unlikely to change their minds, according to the poll.
The polls close at 10 p.m./5 p.m. ET on Friday, and results are expected Saturday afternoon.