Diaz was born and raised in Stockton, California. Nick is the older brother of UFC fighter Nate Diaz and attended Tokay High School in Lodi, California for one year before dropping out. As a freshman, Diaz was a member of the swim team. Diaz has stated that he was very grateful to his mother for getting him into swimming lessons when he was eight years old, as it is one of the main reasons why his cardio is so impressive in his fights, also making triathlons a part of his training.
