After the Broncos' local derby clash against the Gold Coast in Round 7 which they won with a 24-22 win at Suncorp Stadium, Pangai Junior suffered a finger injury during the match and was sidelined for a number of weeks. Pangai Junior would return from injury in Round 13 against the Sydney Roosters in the 18-16 loss at Sydney Football Stadium. Pangai Junior finished the 2017 NRL season with him playing in 18 matches for the Broncos. On 5 October 2017, Pangai Junior was selected in the 24-man squad for Tonga for the 2017 Rugby League World Cup. On 11 November 2017, Pangai Junior made his international debut for Tonga against New Zealand, coming off the interchange bench in the inspirational 28-22 shock win at Waikato Stadium. Pangai Junior would play in the next match for Tonga against Lebanon in their 24-22 win at AMI Stadium in Christchurch. In Tonga’s Semi Final match against England, Pangai Junior scored his first international try, the start of an unlikely Tonga comeback from 20-0 down with 9 minutes to fulltime. As Tonga would dare to dream and score another two more 2 tries to make the score 20-18 with 2 minutes to fulltime, England winger Jermaine McGillvary lost the ball in his own half of the field, Tonga had one more final chance to pinch a stunning victory but unfortunately would end up in tears after Andrew Fifita would go over the tryline on the fulltime siren but the try wasn’t checked by the video referee when the ball was raked out of his hand by England second-rower Elliot Whitehead but was seen by referee Matt Cecchin as a knock on, the match ending in a thrilling fashion 20-18 at Mt Smart Stadium. Pangai Junior finished the exciting tournament with him playing in 3 matches and scoring 1 try.