On 1 February 2016, Radradra again played in the Auckland Nines. On 13 February, he played for the World All Stars against the Indigenous All Stars in the 2016 All Stars match, playing on the wing and scoring a try in his team's 12–8 win at Suncorp Stadium. Early into the 2016 season, he declared that he wanted to play international football for Australia after he found out he was qualified for Australia on residency grounds, so he changed allegiances from Fiji, commenting "I want to be known as the best Fijian rugby player around the world and I want to be playing the top teams," Radradra said. "I want to play alongside all the big names. That's how I made my decision and Australia is the right team for me to showcase my talent". However, while being eligible for Australia, he was ruled ineligible for New South Wales because he did not play junior football in the state before the age of 13. His decision to switch over to play for Australia drew plenty of criticism in the lead-up to the 2016 Anzac Test. On 6 May 2016, Radradra made his debut for Australia against New Zealand in the Anzac Test. He played on the wing and was sin-binned early into the match for a professional foul in the 16–0 win at Hunter Stadium. In June 2016, Radradra was charged with domestic violence which happened in 2014 and 2015 against his ex-partner and it was rumoured that he would not return to play for Parramatta. Radradra finished his highly published 2016 NRL season with him playing in 19 matches and scoring 12 tries for the Eels. On 24 September 2016, Radradra played in the Prime Minister's XIII team against Papua New Guinea, where he played on the wing and scored a try in the 58–0 win in Port Moresby. In October 2016, Radradra was overlooked from Mal Meninga’s 24-man Australia Kangaroos 2016 Four Nations squad due to him being on trial for domestic violence charges.
In late 2016, it was widely rumoured – and later confirmed in January 2017 – that Radradra had signed a one-year deal for French Top 14 club Toulon. The move would not take place until after the 2017 NRL season. Radradra made his debut for Toulon in round 7 of the 2017–18 Top 14 season against Bordeaux. Radradra scored his first try for the club in the European Rugby Champions Cup with his first touch of the game and just 62 seconds into the match on 21 October 2017, against Italian club Benetton. This followed his Toulon debut a fortnight in advance.