The No. 3-ranked receiver in the 2021 class, Hall was one of the stars of last year's spring game and appeared destined to make an instant impact as a freshman.
Hall wound up playing sparingly as a freshman, catching four passes for 72 yards.
He was then suspended by Alabama coach Nick Saban for violation of team rules earlier this month and entered the transfer portal.
At Texas, he'll reunite with head coach Steve Sarkisian, who was Alabama's offensive coordinator during Hall's recruitment.
Alabama and Texas are scheduled to play one another on Sept. 9 in Austin.