Victoria Beckham will not be joining Brown, Chisholm, Horner and Bunton on the tour across the UK and Ireland.
But the group, who burst on to the scene in 1996 with their debut single Wannabe, did not disappoint the thousands of fans who flocked to Croke Park, many of whom had either worn Spice Girls T-shirts or dressed up as their favourite Spice girl.
Irish premier Leo Varadkar, his partner Matt Barrett and Mr Varadkar's sister Sonia were among the 82,000 strong crowd, as was the country's European Affairs Minister Helen McEntee who attended with a group of her friends.
Horner greeted the crowd saying: "Welcome to Spice World. Spice girls, spice boys, everyone is welcome. We want every single one of you to feel special tonight. Like a king or a queen, we celebrate you. But I got to say there are a lot of queens here tonight."
Chisholm told the crowd it was very special for the band to be back in Dublin.
She said: "In '98, we started our world tour in Dublin so we truly are home. It's got a very special place in our hearts."
It is the first time the group has performed since the closing ceremony of the London Olympics in 2012.
The stage, which features an imposing Spice World sculpture and large screens on each side, was used to display messages of female empowerment, including "We are stronger together" and their motto "Girl Power".
Ahead of the first gig, Baby Spice also said she was confident about the comeback, saying "I think we're there."
She told Heart Breakfast: "It's so much fun, being back on stage with the girls. Literally, we giggle to ourselves and of course we make mistakes in the dress rehearsals."
And she said: "I've remembered all the words and I'm just getting to grips with the choreography, so I think we're there."
Bunton added that she really hoped that Posh Spice will see her former bandmates at some point on the tour.
The 13-date Spice World Tour was announced last November.
The band had to deny rumours of a rift in April following Brown's claims that she had a one-night stand with Horner in the Spice Girls' heyday.
But on the opening night, there did not appear to be any tension between the girls, who all laughed and joked with each other throughout the show.
After Croke Park, the Spice Girls will head to Cardiff's Principality Stadium (May 27), the Etihad Stadium in Manchester (May 29 to June 1), Coventry's Ricoh Arena (June 3-4),Sunderland's Stadium Of Light (June 6), Edinburgh's BT Murrayfield Stadium (June 8), Bristol's Ashton Gate Stadium (June 10) and London's Wembley Stadium (June 13-15).