Jan Fernando Martín Sonneborn (born November 20, 1984) is a professional basketball player with three nationalities, Spanish, German, and Israeli.
In his career, he has played at three different positions, center, power forward, and small forward.
He was the first Spanish player to play in the Israeli Super League.
While playing with Maccabi Ashdod in the 2010–11 season, he was chosen as the Israeli League Rising Star.