President Michael D Higgins has signed a bill into law, that cuts divorce times in half.
The Family Law Bill 2019 only passed through the Oireachtas on Wednesday.
In May, 82% of voters backed the proposed changes - including reducing the minimum 'living apart' period for couples looking for a divorce to two of the previous three years.
Results showed that every constituency in the country voted in favour of the measure.
Just 17.93% of people voted against it, with turnout at 50.83%.
Previous divorce laws had required couples to have lived apart for four out of the previous five years.
The new law also recognises divorces, legal separations and marriage annulments granted in the UK in the event of a no-deal Brexit.
It also offers more clarity on the meaning of the 'living apart' requirement.
At the time of the vote, executive director of the Irish Council for Civil Liberties (ICCL), Liam Herrick, said: "With this vote, we have taken a huge leap towards protecting the rights of people who need a divorce.
"It will also help to ensure that people who are stuck in dangerous or financially and emotionally distressing situations can be freed from them."
Karen Kiernan, CEO of One Family, said: "This vote is a big step towards making Ireland a more compassionate and humane place for people going through a divorce.
"We know from our work with families separating that on a practical level it will reduce stress and financial expense for families."
And Eilis Barry, chief executive of the Free Legal Advice Centres (FLAC), said it was a "much needed step" to reduce the pressure on divorcing couples navigating the legal system.