Hafsteinn Ægir Geirsson (born 4 August 1980 in Reykjavík) is an Icelandic cyclist and retired sailor, who specialized in the Laser class.

[1] He represented his nation Iceland in two editions of the Olympic Games (2000 and 2004), and has also been training throughout most of his sporting career for Þytur Sailing Regatta (Icelandic: Siglingaklúbburinn Þytur).

[2] Hafsteinn made his official debut at the 2000 Summer Olympics in Sydney, where he placed forty-second in the Laser class with a net grade of 355, after having decided to pull himself out in the last race due to yachting malfunction.

[3][4] At the 2004 Summer Olympics in Athens, Hafsteinn qualified for his second Icelandic team, as a 24-year-old, in the Laser class by granting a tripartite invitation from the International Sailing Federation.

[5][6] Sailing through the race series with a similar effort from the previous Olympics, Geirsson recorded a satisfying grade of 344 net points to upgrade his position to fortieth in a fleet of forty-two sailors.