Siaosi Mahoni Bio
Siaosi “CC” Mahoni is an American international rugby union player who plays as a lock for the Seattle Seawolves in Major League Rugby (MLR). Standing 6 feet 8 inches tall and weighing around 295 pounds, he brings a powerful physical presence to the second row. Of Tongan descent, Mahoni has built a professional career that has taken him from the first professional rugby competition on American soil to stints in France and across multiple MLR franchises.
Early Life and Background
Siaosi Mahoni was born on January 29, 1997, in East Palo Alto, California, in the United States. He grew up in a region with a long and proud tradition of Polynesian athletic talent, and his Tongan heritage has been a notable part of his identity throughout his rugby journey. His towering frame, which eventually reached 6 feet 8 inches, suggested early on that he was suited for the physical demands of forward play.
Before turning professional, Mahoni played amateur rugby in his hometown with the East Palo Alto club, where he developed the basics of the sport. That grassroots grounding in a community-centered program helped shape the work ethic and physical edge that would later define his career at the professional level.
Path to Professional Rugby
Mahoni’s entry into professional rugby came in 2016, when he joined the San Francisco Rush of PRO Rugby, the first professional rugby competition to operate in the United States. Playing for the Rush gave him early exposure to high-level senior rugby and put him on the radar of scouts both at home and abroad. That same year, he also represented the USA Selects, signaling his standing within the American player pipeline.
In 2017, Mahoni earned his first cap for the United States national team, a significant milestone that confirmed his arrival as a top-tier American lock. Shortly after, he took his game overseas, signing with RC Narbonne in France for the 2017 to 2018 season, where he gained valuable experience in one of the most demanding rugby environments in the world.
Siaosi Mahoni Career
Early Career (2016)
Mahoni’s professional career began in 2016 with the San Francisco Rush in PRO Rugby, the short-lived but historically important first professional rugby league in the United States. Although the league lasted only a single season, his involvement marked him as part of a foundational group of American-based professionals who helped prove the sport could be played at a high level domestically.
During that debut season, he balanced his club duties with selection for the USA Selects, an invitational side that showcased emerging American talent. His early form with both the Rush and the Selects was enough to earn a senior international cap the following year and to attract interest from European clubs.
RC Narbonne Era (2017–2018)
Following his breakout year, Mahoni moved to France to play for RC Narbonne, a traditional club in the French rugby system. Competing in France exposed him to a faster, more tactically intricate style of forward play and gave him the chance to test himself against seasoned European professionals. The experience sharpened his set-piece work and broadened his understanding of the global game.
His time at Narbonne was brief but formative, and it helped him return to the United States as a more complete lock. It also reinforced his reputation as a player willing to take on new challenges in unfamiliar rugby cultures.
San Diego Legion Era (2018–2021)
After his stint in France, Mahoni returned to California to join the San Diego Legion ahead of Major League Rugby’s growing years. With the Legion, he became a regular presence in the second row during a formative era for the league, contributing to one of MLR’s most competitive rosters. He spent three seasons in San Diego, establishing himself as a reliable and physical lock at the top level of American rugby.
During his time with the Legion, Mahoni continued to develop his lineout work, defensive reads, and ball-carrying around the contact area. His consistency in the San Diego engine room made him a respected figure in the Western Conference.
Houston Sabercats Era (2022–2024)
In 2022, Mahoni made the move to Texas, joining the Houston Sabercats. His arrival in Houston added size and experience to a Sabercats pack that was building toward contention in MLR. Across three seasons with the club, he provided leadership in the second row and contributed to the team’s set-piece stability.
Mahoni’s tenure in Houston coincided with the Sabercats’ push to become a consistent playoff presence, and his experience from both MLR and French rugby helped anchor the forward unit. By the end of his time there, he had become a well-known figure within the MLR community.
Seattle Seawolves Era (2025–Present)
In 2025, Siaosi Mahoni joined the Seattle Seawolves, one of the most decorated franchises in Major League Rugby history. The move brought him to a club with multiple championship appearances and a strong winning culture, offering him a fresh opportunity to compete for silverware. His signing added another veteran presence to an already talented Seawolves forward pack.
Driving Style and Strengths
Mahoni’s game is built around his imposing 6-foot-8 frame, exceptional lineout reach, and physicality in close-quarter exchanges. He excels in set-piece scenarios, where his height and timing make him a reliable target in the air, and he is equally effective in tight defense, where his size disrupts opposition ball carriers. His time in France also gave him a more tactically disciplined approach to forward play, complementing his raw athletic gifts.
Notable Events and Milestones
One of the most significant milestones in Siaosi Mahoni’s career came in 2016, when he was part of the San Francisco Rush squad in PRO Rugby, the first professional rugby competition held in the United States. The following year, he earned his first cap for the United States national team, a marker of his standing among the country’s top locks. His career path, from a California amateur side to France and back through multiple MLR franchises, stands as a notable arc within American rugby’s modern professional era.
Siaosi Mahoni Career Highlights
Across his professional career, Siaosi Mahoni has built a resume that spans professional leagues in the United States and France. He debuted professionally in 2016 with the San Francisco Rush in PRO Rugby, earned a senior United States cap in 2017, and has since appeared for RC Narbonne, the San Diego Legion, the Houston Sabercats, and the Seattle Seawolves.
Major League Rugby Highlights
In Major League Rugby, Mahoni has played for the San Diego Legion from 2018 to 2021, the Houston Sabercats from 2022 to 2024, and the Seattle Seawolves from 2025 onward. He has been a regular contributor in the second row throughout his MLR career, providing lineout security and physicality in the tight phases of the game.
Other Performances
Outside of MLR, Mahoni represented the San Francisco Rush in the inaugural season of PRO Rugby in 2016 and spent the 2017 to 2018 season in France with RC Narbonne. He also earned selection for the USA Selects in 2016, highlighting his early standing in the American rugby pipeline before his senior international debut the following year.
Siaosi Mahoni Family
Family Background and Heritage
Siaosi Mahoni is of Tongan descent, a heritage that connects him to one of the most celebrated rugby cultures in the Pacific. Growing up in East Palo Alto, California, he was raised in a community with deep Polynesian roots, and that background has remained a meaningful part of his personal and athletic identity.
Personal Life
Mahoni is known professionally by the nickname “CC,” a name widely used by teammates, fans, and media. He has spent much of his rugby career in the United States, with a brief professional chapter in France, and continues to be recognized as one of the experienced American locks in Major League Rugby.
2025 Season Performance
The 2025 Major League Rugby season marks Siaosi Mahoni’s first year with the Seattle Seawolves after three seasons in Houston. Joining one of the league’s flagship franchises, he entered the season as a key addition to the Seawolves’ forward pack, bringing size, set-piece experience, and a winning mentality cultivated across multiple clubs.
Mahoni’s role with the Seawolves in 2025 centers on stabilizing the lineout, anchoring the defensive line, and providing veteran leadership in tight matches. His familiarity with MLR’s pace and physicality, gained from years with the San Diego Legion and Houston Sabercats, has allowed him to slot into Seattle’s system with relative ease.
With the Seawolves consistently in the hunt for playoff success, Mahoni’s presence adds another layer of depth to a roster aiming for another deep postseason run. His continued development and on-field impact will be a storyline to watch as the 2025 season unfolds.