On 21 December 2015, the Japan Rugby Football Union announced Hammett as the head coach of the newly formed Japanese Super Rugby franchise, the Sunwolves. In their debut season, the side finished bottom of the newly expanded table, with 1 win. Ironically, their win came against the other newly formed team, the Jaguares, a team made up predominantly of the successful Argentine side from the 2015 Rugby World Cup. On 27 June, it was announced that Hammett would be leaving the Japanese side to return to New Zealand. It had previously been announced that Hammett would be joining the Tasman Makos in 2016 as their new assistant coach for the 2016 Mitre 10 Cup. While in June 2016, it was announced that Mark Hammett will remain in Super Rugby, but as an assistant coach at the Highlanders.