Mwata, a three-star recruit according to several recruiting websites, plays at the same high school that produced outgoing BYU safety Kai Nacua, Liberty High School.
"Blessed and proud to announce that I am committed to Brigham Young University!" Mwata tweeted Saturday evening shortly after the Cougars concluded their BYU FanFest event in North Las Vegas.
Mwata recorded 48 tackles and made three interceptions in 2016, his junior season, for Liberty High, which won the Sunrise Region championship. He also had a scholarship offer from Florida Atlantic, according to the Las Vegas Sun.
Mwata is the 12th football prospect from the class of 2018 to commit to BYU.
However, three commits have already decommitted: defensive tackle Tyler Manoa of Hayward, Calif.; defensive end Cameron Latu of SLC's Olympus High, and punter Sekope Latu of Kahuku, Hawaii.
Several of the players who have committed to BYU, including Herriman's Jaren Kump and Brandon Kaho of Reno, Nev., are considered "soft" commits because they are still entertaining offers from other schools.
Kaho, a four-star linebacker, recently visited Stanford and Washington.
"I am still committed to BYU and pretty strong with them, but I am just looking into all the schools that are expressing a lot of interest in me," Kaho told Scout.com last week.
Kaho told the website he is being recruited to Stanford by defensive coordinator Lance Anderson, who is LDS and has persuaded several high-caliber LDS prospects to bypass BYU (and others) for Stanford in recent years.
Here's the list of BYU's current 2018 football commits:
Campbell Barrington, 6-6, 280 DE from Spokane, Washington (University High School)
Connor Pay, 6-5, 270 OL from Highland, Utah (Lone Peak High School)
Nathan Latu, 6-5, 212 OLB from Salt Lake City, Utah (Olympus High School)
Brandon Ale Kaho, 6-3, 215 LB from Reno, Nevada (Reno High School)
Jaren Kump, 6-5, 250 DE from Herriman, Utah (Herriman High School)
Tevita Fotu, 6-3, 215 DE from Herriman, Utah (Herriman High School)
Jacob Smith, 6-6, 290 OL from Rosemount, Minn. (Rosemount High School)
Dallin Holker, 6-4, 220 TE from Lehi, Utah (Lehi High School)
Allan Mwata, 6-0, 170 DB from Henderson, Nev. (Liberty High School)