 Sione's early career consisted of 4 years of playing rugby sevens in Japan with the Asahi University.While he was playing in Japan he was scouted by Afa Hanipale who recommended him to invitational team Samurai RFC.Sione was invited to play for Samurai RFC at the Hong Kong 10s tournament in 2017

It was at the Hong Kong 10s, playing for Samurai RFC, that he impressed the then Saracens Academy Director Donald Barrell.