In March 2015, Helstrup was loaned for four months to Swedish club Helsingborgs IF, coached by Henrik Larsson. On 4 April 2015, he made his Allsvenskan debut in a goalless match against Kalmar FF. Before the end of the loan period, the club decided to sign Helstrup on a permanent transfer. For two consecutive seasons he was a starter in the defense. After the 2016 season ended, Helsingborgs IF suffered relegation to Superettan, after losing 2–3 to Halmstads BK. Helstrup played in both matches, scoring an own goal in the first one.