Mo'unga was a member of the
New Zealand Under 20 side, which finished 3rd in the
2014 IRB Junior World Championship in New Zealand, where he scored 29 points in 5 games. Mo'unga represented the
Barbarians against
New Zealand, on 4 November 2017, at
Twickenham Stadium,
London. Mo'unga scored 7 points, scoring the game's opening try and also converting a Barbarian try in the 31st minute. After the
Barbarians match, Mo'unga joined the All Blacks for their Northern Tour, having warranted a place in the squad through his performance in the Mitre 10 Cup. Mo'unga was named on the bench for a New Zealand side for a midweek game against a French side. He converted a try by lock
Patrick Tuipulotu after coming on as a replacement in the second half. This match however did not count as an official test match. Mo'unga made his official test debut on 23 June 2018 against France during the
France test series where he replaced
Damian McKenzie in the 69th minute. The All Blacks won 49–14. Mo'unga made his first ever start for New Zealand during Round 3 of the competition, on 8 September 2018. Mo'unga led the All Blacks to a 46–24 victory over Argentina by scoring 16 of the team's points. Mo'unga only missed one kick on the night and lasted the full 80 minutes. Mo'unga's starting performance against Argentina saw him temporarily overtake Damian McKenzie, as backup to regular starter
Beauden Barrett. This saw Mo'unga feature off the bench against Argentina and South Africa in the final two rounds of the competition. Mo'unga replaced winger
Waisake Naholo, in the 51st minute against South Africa, with
Ben Smith moved to wing, and Beauden Barrett moved into fullback, to accommodate for Mo'unga at first-five. Mo'unga took kicking duties off Barrett, who had missed a drop goal during the match. Mo'unga converted
Ardie Savea's last minute try, after the 80th minute, winning the game for the All Blacks, making the final result against South Africa 32-30. Mo'unga finished as one of the highest points scorers of the Rugby Championship, with 24 points. This ranked Mo'unga 6th of all the points scorers. Mo'unga remained unable to become a regular starter for New Zealand on the
2018 end of year tour. After replacing McKenzie in the third Bledisloe Cup test, against Australia, in a 37–20 win, Mo'unga earned a start against Japan on 3 November. Mo'unga scored 22 points during New Zealand's 69–31 win over Japan, including his first international try. Mo'unga stayed on for the full 80 minutes, with debutant first-five,
Brett Cameron, instead replacing
Waisake Naholo, although Utility Back,
Jordie Barrett, did kick some goals towards the end of the test against Japan, in which Mo'unga was one of the best performers. He made an appearance in every test on the end of year tour, coming off the bench in the final three, which were wins against England and Italy, as well as a 9–16 loss to Ireland. Named in the All Blacks squad for the
2019 Rugby Championship, Mo'unga was named at first-five-eighth after starting fullback Damian Mckenzie was ruled out of the tournament with an ACL injury. The All Blacks starting five-eighth,
Beauden Barrett was shifted to fullback, as part of a continuation of the dual playmaker system, while
Waisake Naholo was dropped from the national setup entirely to make room for Mo'unga and Barrett's combination. After New Zealand's 16–16 draw with South Africa and record 26–47 loss to Australia the Mo'unga and Barrett combination was criticised in New Zealand widely. With many fans and media alike both favouring the experience of veteran Ben Smith at fullback, and 2 time player of the year, Beauden Barrett, at first five-eighth. However, Mo'unga grabbed a 14-point haul against Australia in the second
Bledisloe Cup test against Australia for the year, before being replaced by
Jordie Barrett. The 36–0 win over Australia saw Mo'unga sustain a shoulder injury, which ruled him out for one test, against Tonga. On 28 August 2019, All Blacks Head Coach,
Steve Hansen, named Mo'unga as one of 31 players selected in New Zealand's squad for the
2019 Rugby World Cup. Mo'unga was named as the only specialist first five-eighth in the squad, with the injured
Damian McKenzie, as well as single cap All Blacks,
Brett Cameron and
Josh Ioane missing out. Mo'unga started at first five-eighth throughout the tournament, winning the man of the match award against Canada. After a solid display against Ireland in the quarter-finals, Mo'unga and the All Blacks were knocked out of the 2019 Rugby World Cup at the semi-finals against England, losing 19-7. Mo'unga was retained at first-five for the third place play off, where he led them to a 40–17 victory over Wales. == Personal life ==