One of the first ceremonies in New South Wales took place overnight near Tweed Heads, where athletes Craig Burns and Luke Sullivan timed their proceedings so the marriage would become official minutes after midnight.
"It's a very surreal feeling," Craig told AAP in the lead-up to the event.
The pair first met three years ago and said they fell in love "straight away" before Craig popped the question at Byron Bay in March.
Same-sex marriage legislation cleared parliament on December 7 last year, nearly a month after it was revealed 61.6% of participants in a voluntary postal survey backed the change.
Amid scenes of jubilation same-sex couples were quick to lodge formal intentions to wed and while some were granted exemptions to the four-week waiting period, Tuesday is the first official day ceremonies can take place.
In Newcastle, 32-year-old Rebecca Hickson is now officially married to her partner of nine years Sarah Turnbull (34).
The pair also wanted to be part of history as one of the first couples to wed, doing so in a ceremony at 8am.
"We have a real certificate - it feels amazing," Rebecca told AAP after today's ceremony. "We are wife and wife."
The pair, who had a "big hoo-ha" commitment ceremony three years ago was more than happy to declare their love for each other again.
"It's not just a commitment ceremony, now we are legally married so it's recognised by everyone," a jubilant Sarah said after the ceremony. "We are over the moon."
Rebecca described the build-up to the postal vote deadline as "a horrible time" but said the couple are now excited to move beyond it.
Melbourne couple Ron Van Houwelingen (50) and Antony McManus (53) echoed Ms Hickson's feelings about the postal vote and said no country should have to endure the same "horrendous" process to legalise gay marriage.
On Tuesday, the long-time activists will also look forward and marry where they first met as performing arts students three decades ago - at the former Prahran College of TAFE's David Williamson Theatre.
"I'm looking really forward to celebrating the victory," Ron told AAP.
The two have already held more than a dozen commitment ceremonies, including in 1993 on their sixth anniversary when gay marriage "wasn't on the radar".
"I suppose it's been a wedding planned for 30 years but we've had really a month to get things together," Ron said.
"It's been quite hectic trying to organise that in such a short amount of time."
Labor leader Bill Shorten tweeted his best wishes to those getting married today.
"To every couple tying the knot today and in days to come, congrats from Chloe and I.
"The wait is finally over. #loveislove" he tweeted.
