Johannes Ahun (born 22 December 1987) is a former Estonian windsurfer, who specialized in Neil Pryde RS:X discipline.

He quit professional sports career in 2015 and went to study sound engineering at University of Tartu Viljandi Culture Academy.

[4] Ahun was born in Tallinn, and began surfing at the age of eleven, when he was encouraged by his father to visit the beach, especially during the winter season.

Two years later, Ahun was admitted to the national senior sailing team, and had been participating in numerous windsurfing competitions, including his official international debut at the 2006 RS:X World Championships in Nago–Torbole, Italy.

Ahun competed for the first time at the 2008 Summer Olympics in Beijing, where he sailed in the men's RS:X windsurfing, finishing in thirty-third place after ten races, with a total of 273 net points.