Expat voters flock home to have their say
Expat voters took to social media as they headed home to vote in the referendum.
Various hashtags have appeared on Twitter throughout the day, including #hometovote.
One user, Ali Mason, flew all the way from America to have her say.
She tweeted: "I flew from San Francisco to vote Yes today. No biggie. #hometovote"
Musician Hozier also tweeted a selfie with the caption: "Eire! Have some hrs free, flying in to vote tomorrow. It's the most important thing you'll do. Don't forget! #MarRef"
Pictures showing trains between London to Holyhead packed with people travelling home and queues for flights to Ireland were retweeted thousands of times.
Reuters reporter Naomi O'Leary tweeted "Rousing rendition of 'Ta na gays ag teacht abhaile' fills Holyhead port #hometovote" - a Gaelic phrase which translates "the gays are coming home".
Some people were unable to return to the country in time and - because postal voting was not available - started the hashtag BeMyYes, encouraging others to vote in support of gay marriage.
Actress and singer Susan McFadden tweeted: "Wish I was at home tomorrow to give my YES vote.. Come on Ireland let's show the rest of the world how it's done.. #equality #BeMyYes"
Other Irish celebrities to add their voice to the campaign day included comedian Ed Byrne, who said on twitter: "Right now I'm as far from Ireland as it's possible to be but I'd still like to wish all the yes voters a happy #MarRef day."
UFC title challenger Conor McGregor also tweeted his support for the Yes movement, saying: "Myself and my team are urging everyone to please VOTE YES TO EQUALITY! Every human deserves equal rights #WeAreAllOne".