In May 2018, Karačić was named in Australia's preliminary 26-man squad for the 2018 FIFA World Cup in Russia.[5] On 25 May 2018, he was officially cleared by FIFA to represent Australia.[6] Karačić was later cut from the final squad.[7][8]
Karačić was called up to the Australian squad again for a series of 2022 FIFA World Cup qualifying games in June 2021, where he made his international debut against Kuwait.[9]