Top 2026 basketball recruit transfers to new California high school

Brannon Martinsen, a 4-star forward in 2026, has transferred from Southern California power Mater Dei to league rival JSerra.

Mater Dei's Brannon Martinsen wins MVP at the 2024 Hoophall Classic in Springfield, Mass. / Tarek Fattal

One of Southern California's top high school basketball players is on the move.

Brannon Martinsen, a 6-foot-7 junior, has checked out of Mater Dei and has transferred to Trinity League foe JSerra. Sources confirmed Martinsen is enrolled at JSerra and is expected to start class Tuesday of this week.

Frank Burlison (Burlison on Basketball) was the first to report Martinsen left Mater Dei on Sunday, Sept. 8.

Mater Dei and JSerra are scheduled to play on January 15 and 29.

Martinsen is the second marquee player to leave Mater Dei since the 2024 season ended. Forward Brandon Benjamin, who transferred from Anaheim Canyon, has transferred back to Canyon for his senior campaign.

Martinsen is a 4-star rated prospect, according to 247Sports, with offers to USC, Stanford, Creighton and Illinois.

Since Martinsen was a freshman, he's been a marquee name on the Monarchs' roster. He helped Mater Dei win the CIF Southern Section Division 1 title in 2023 and anchored the team's berth to the Open Division playoffs in 2024. He was named All-CIF in both seasons.

Martinsen wasn't able to compete in last year's postseason after suffering a lower leg injury late in the regular season when playing against St. John Bosco. Still, Martinsen was the team's leading scorer at 17 points per game. He also tallied six rebounds per contest as a sophomore.

The long, wiry forward was also named Player of the Game in Springfield, Mass. when the Monarchs played at the Hoophall Classic and defeated Catholic Memorial (MA) 87-69. Martinsen had 21 points and 10 rebounds.

Mater Dei returns sharpshooter Luke Barnett for the 2024-25 season, who made 113 3-pointers and averaged 15 points per game as a sophomore. Guard Owen Berna and forward Blake Davidson also return to play for longtime coach Gary McKnight.

FINAL from @HoophallClassic
Mater Dei 87, Catholic Memorial (MA) 69

Brannon Martinsen 21pts, 10rebs; Blake Davidson 13pts, 14rebs; Brandon Benjamin 14pts

Monarchs had 22 off. rebounds and 34 second-chance points. pic.twitter.com/j2DUGj51pD

— Tarek Fattal (@Tarek_Fattal) January 13, 2024

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