Dayday Aupiu is a defensive back for the California Golden Bears who stands 6'2" and weighs 170 pounds. The Oxnard, California native from Pacifica High School was a consensus three-star recruit in the 2024 class. At the prep level, Aupiu recorded 215 tackles, 10.0 tackles for loss, 11 interceptions returned for 103 yards and three touchdowns, along with 28 pass breakups. He also logged 37 receptions for 387 yards and five touchdowns. As a redshirt sophomore in 2025, Aupiu appeared in all 13 games and recorded one tackle against Stanford.