Billie Kay and Peyton Royce were first teamed up shortly after joining NXT, although they would only appear in house shows for over a year. Their first match as a team was on May 8, 2015 at a house show in Largo, Florida, where they lost to Bayley and Carmella. For a period of over a year, the two were used as jobbers and lost all of their matches as a team, although they won a few separately.
The team made their television debut on the October 5, 2016 episode of NXT, and were later dubbed "The Iconic Duo". Almost a year and a half after the creation of their team, the duo picked up their first win on October 14, 2016 at a house show in Fort Pierce, Florida, defeating Aliyah and Liv Morgan. They also won their first match on television on the December 28, 2016 episode of NXT, defeating Aliyah and Morgan again. On January 28, 2017 at NXT TakeOver: San Antonio, the two were voted 2016's "Breakout of the Year" at the NXT Year-End Awards; they also competed at the event in their live television debut, both losing in a fatal four-way match for the NXT Women's Championship won by defending champion Asuka.
At NXT TakeOver: WarGames, Royce unsuccessfully competed in a fatal four-way match for the vacant NXT Women's Championship against Kairi Sane, Nikki Cross, and winner Ember Moon. The duo's final televised match on NXT television was on the October 4, 2017 episode of NXT in a loss against Cross and Ruby Riott, although they kept on competing in house shows; their final match as a part of the NXT brand was on April 21, 2018 at a house show in Fort Pierce, Florida, where they lost against Dakota Kai and Steffanie Newell; after the match, both teams hugged each other.
Kay and Royce, now known as "The IIconics", debuted on the April 10, 2018 episode of SmackDown Live, attacking SmackDown Women's Champion Charlotte Flair, allowing Carmella to cash in her Money in the Bank contract and defeat Flair to win the championship. The following week on SmackDown, The IIconics won their first match on the main roster by defeating Asuka and Becky Lynch. On October 6 at Super Show-Down, in their native country, they defeated Asuka and Naomi.
In 2019, The IIconics entered their first Royal Rumble match at the eponymous event, eliminating Nikki Cross before being eliminated by Lacey Evans. The following month at Elimination Chamber, they participated in the first female tag team Elimination Chamber match to determine the inaugural holders of the WWE Women's Tag Team Championship, eliminating Naomi and Carmella before being eliminated by Nia Jax and Tamina; the match was ultimately won by The Boss 'n' Hug Connection (Bayley and Sasha Banks). In March, The IIconics started a feud with The Boss 'n' Hug Connection, whom they defeated in a non-title match on the March 19 episode of SmackDown. Because of their win, they (and two other teams) challenged Banks and Bayley for the championships at WrestleMania 35 in a fatal four-way tag team match. At the event on April 7, The IIconics won the Women's Tag Team Championship after Kay pinned Bayley. Their win made them the first all-Australian tag team champions in WWE history, and the first Australians to win a title at WrestleMania.
Two days later on SmackDown, in their first title defense, The IIconics defeated Kris Statlander and Karissa Rivera. On the June 17 episode of Raw, the IIconics successfully defended their titles against Alexa Bliss and Nikki Cross. On the July 16 episode of SmackDown, The IIconics retained their titles against The Kabuki Warriors (Asuka and Kairi Sane) via count-out.
On the August 5 episode of Raw, the duo lost the titles to Bliss and Cross in a fatal four-way elimination match. They were the first team eliminated in the match, being knocked out by Mandy Rose and Sonya Deville. Their reign ended at 120 days.
On October 16, it was announced that The IIconics had been drafted to Raw as supplemental picks of the 2019 WWE Draft. On October 28, the IIconics lost in a tag team match against Charlotte Flair and Natalya.
The team made their return on the May 11, 2020 episode of Raw, interrupting WWE Women's Tag Team Champions Alexa Bliss and Nikki Cross. They later defeated the champions in a non-title match. They unsuccessfully challenged for the WWE Women's Tag Team Championships multiple times throughout the summer. They also feuded with Ruby Riott, mocking her backstage for not having any friends. They would go on to trade victories as Kay and Royce defeated Riott while Riott defeated Kay. At Payback, The IIconics were defeated by Riott and her newly reunited tag partner Liv Morgan. The following night on Raw, The IIconics were forced to disband after losing to The Riott Squad per stipulation.
During the 2020 WWE Draft, Royce was drafted to Raw while Kay was drafted to SmackDown, solidifying the breakup.