In June 2015, Grenoble announced that Taumalolo would join the club ahead of the 2015–16 Top 14 season. During that first season, he played with Grenoble for the European Rugby Challenge Cup. However, after his second season with the club, Grenoble was relegated to the Pro D2 for the 2017-18 season. Their stay in the Pro D2 didn't last long; at the end of the season, the club secured promotion back to the Top 14 for the 2018-19 season after defeating Oyonnax in a promotion/relegation match. Taumalolo scored a total of 8 tries that season, including one try in that last match.