Halvorsen moved to Italy to join National Championship of Excellence side Mogliano prior to the 2013–14 season. He immediately established himself as the first-choice number eight at Mogliano, starting 18 of their 22 matches during the season and scoring two tries. Mogliano finished in third position on the log and Halvorsen featured in their 19-22 and 30–31 defeats against Rovigo in the two-legged semi-final. In addition to the National Championship of Excellence, Halvorsen also made five appearances in the 2013–14 European Challenge Cup. His side had a poor season in Pool 2 of the competition, however, losing all six of their matches.