UP Fighting Maroons On August 1, 2020, it was announced that both Tamayo and Abadiano had committed to the
UP Fighting Maroons. He cited his aunt, a
University of the Philippines graduate, as one of the reasons he chose UP. His arrival led to premature comparisons to center
Benjie Paras, who led UP to a UAAP title in
1986. Several weeks later, their high school coach Monteverde resigned from NU, who was supposed to be the head coach for the senior team of NU. Another former teammate, Cyril Gonzales, left
Mapúa to join them at UP. In 2021, two more of Tamayo's former teammates reunited with him at UP, with guards Fortea and
Harold Alarcon also committing to UP. That year, Coach Monteverde was named head coach for the Maroons, reuniting him with many of his former players.
Rookie season: UAAP seniors' championship Tamayo made his UAAP seniors' debut in
Season 84 in a loss to the
Ateneo Blue Eagles with 13 points and 10 rebounds. In UP's 5th straight win, he had nine points and 11 rebounds against the
La Salle Green Archers. They extended the win streak to seven against the
NU Bulldogs, with him scoring 21 points, 10 rebounds, and three steals. Their win streak ended at eight with a loss to the
Adamson Soaring Falcons. They bounced back with a win over La Salle, in which he had a career-high 23 points with 11 rebounds. They faced La Salle again in the Final Four. In Game 2, with UP down by 14 points with seven minutes in the game, he scored 12 of his 19 points in that period that led to UP having a 76–74 lead with 21.4 seconds remaining. La Salle guard
Evan Nelle had a chance to tie the game with a layup, but it missed which Tamayo rebounded. He then made two free throws to seal a 78–74 win that sent UP back to the Finals. He finished the game with 19 points, 10 rebounds, four steals, and three assists. This set them up for a best-of-three Finals match against defending champions Ateneo. In Game 1, he had 10 points, nine rebounds, five steals, three assists, and two blocks in the overtime victory. Before Game 2, he was awarded UAAP Rookie of the Year. He also made it to the Season 84 Mythical Five, along with his teammate
Zavier Lucero. In Game 2, he had 18 points, 12 rebounds, and two steals, but Ateneo won the game. In Game 3, he only had six points, but UP won the game with
JD Cagulangan making the game-winning shot. This ended UP's 36-year title drought and made him a champion once again.
Sophomore and final season: Runner-up finish Tamayo started the title defense campaign with a close win over the Green Archers in which he produced 18 points, 19 rebounds and two clutch free throws. Against the
FEU Tamaraws, he had 16 points (with eight coming in the fourth quarter) as the Maroons scored their third straight win. The Maroons suffered their first loss of the season against the Bulldogs, despite his 17 points and 11 rebounds. In a rematch against Ateneo, he had a costly turnover in the last 20 seconds of regulation, but he bounced back in order by scoring six of his 20 points in overtime and got UP the win. He then had 13 points, seven rebounds, and four steals in a win over the
UE Red Warriors, but he sprained his ankle in the final minute of that game. Coach Monteverde said after the game that the injury was minor. He was able to play the next game as UP coasted to an easy win over the
UST Growling Tigers. At the end of the first round, he was in the top 5 in the MVP race. In the second round, Tamayo scored 18 points in a rout of Adamson. They continued their win streak until the Green Archers stopped their streak at seven, despite his 14 points and seven rebounds. He then led all scorers with 19 points to go along with his nine rebounds as UP beat UST once again. UP made the Finals once again by beating NU in the Final Four. The Maroons won Game 1 despite him being limited to seven points, four rebounds, two assists, one steal, and one block. Before Game 2, he won a spot in the UAAP Mythical Five and P30,000 for the
Lazada Swag Player of the Season, a fan award. His teammate
Malick Diouf was also on the Mythical Team and won the MVP award. Ateneo however, bounced back in Game 2. He only had 11 points and nine rebounds in Game 3 as despite the Maroons' efforts, the Blue Eagles won the championship. On January 10, 2023, Tamayo announced that he will leave UP to play in the Japanese
B.League. ==Professional career==