Project 51O

Ali Elmasnaouy scored in extra time against El Farolito in the 2024 U.S. Open Cup, and that goal is the one Project 51O's supporters tend to bring up. He was the club's Player of the Year that season and the Southwest Division Player of the Year in USL League Two. In July 2025 he signed his first professional contract, with Oakland Roots SC.

That move is what the club exists for. Project 51O was set up in 2019 as the reserve and development side of Oakland Roots, and its name comes from Oakland's 510 area code, with the "O" standing for the city. It played its first competitive season in 2020 in the National Premier Soccer League (NPSL). Joseph Restani scored the club's first goal in the opening game, against Napa Valley 1839 FC, and signed for Roots in 2021. When Roots were promoted to the USL Championship that year, 51O moved up to USL League Two to give local players a direct route into the first team. Ilya Alekseev followed in 2024, signing after two goals for the senior side.

The Southwest Division title in 2022 brought a place in the 2023 Lamar Hunt U.S. Open Cup, the club's first appearance in the tournament. In 2024 the side reached the Western Conference Finals of the League Two playoffs, its deepest run in that competition. Away from the league, 51O won the Street Soccer USA Oakland Cup, played around Día de los Muertos, in 2023 and 2025.

Matches against San Francisco Glens and San Francisco City FC are treated locally as East Bay against San Francisco, though the fixture has no official derby name. The team plays at Merritt College Soccer Stadium in black at home and white away, as the parent club does. In the UPSL, 51O won the NorCal South regular-season title in both 2024 and 2025.