Following one season in Japan, Naoupu returned to play for Connacht in the 2011–12 season. When he returned the Celtic League had been renamed the Pro12, and Connacht had qualified for the Heineken Cup, Europe's top club competition, for the first ever time. Naoupu made his first appearance since returning in the opening game of the 2011–12 Pro12, starting against Benetton Treviso on 3 September 2011, and playing the full 80 minutes. Naoupu made his first appearance at the top level of European rugby on 11 November 2011, when he started against Harlequins in Connacht's opening 2011–12 Heineken Cup game. Naoupu also started in all five other games the province played in the competition, including Connacht's first ever win at that level, in the return game with Harlequins on 20 January 2012. He made a total of 17 league appearances for the season, starting in all the games he played.