Collier is the No. 90 overall prospect on the ESPN 300 and second-ranked player at his position.
The Miami native's commitment comes a day after No. 2 cornerback Jason Marshall spurned his hometown Hurricanes to join head coach Dan Mullen in Gainesville.
Collier adds to a solid class for Florida, representing the school's third top-100 recruit for 2021. The Gators landed four such prospects last year.
The safety received offers from a number of big-time programs - including Clemson, Georgia, and LSU - and also considered joining Florida State.