Billy enters his third season as an assistant coach and player development coordinator for the Stanford beach volleyball program in 2026.
The 2025 season of Stanford beach volleyball continued to write new pages in the history books as the program secured its first-ever conference title in its inaugural season as a member of the Mountain Pacific Sports Federation (MPSF) while matching the program’s single-season wins record and taking down two No. 1-ranked opponents in the process. The Cardinal captured 18 top-20 ranked wins throughout the 2025 season, including victories over two top-ranked teams (USC (Feb. 21), UCLA (April 24)) and an upset of then-No. 3 Cal Poly (April 11). Stanford extended its streak of NCAA Championships appearances to five, tying its highest ever seeding (No. 3 overall seed) to enter the single-elimination tournament. The incredible year was highlighted during awards season, where the Cardinal saw four student-athletes named AVCA All-Americans, secure a conference-leading eight MPSF all-conference honors, junior Kelly Belardi and Charlotta Bell earn an AVCA Top-Flight award while being named MPSF Tournament Most Valuable Pair and to the MPSF All-Tournament Team, freshman Avery Jackson and sophomore Brooke Rockwell selected to the MPSF All-Tournament Team, and seven named to the inaugural MPSF All-Academic Team.
His first season on The Farm was a historic one, as Stanford cemented its position as one of the best programs in the country, guided by its best-ever record (32-6) and 21 wins over top-ranked teams from across the nation. The Cardinal recorded seven all-conference honors, including Brooke Rockwell's Freshman of the Year award, and had four AVCA All-American selections for the first time in program history.
Allen joins the Cardinal after a season spent across the Bay, most recently serving the California Golden Bears indoor volleyball program as an assistant coach for the 2023 season. Allen helped coach the Bears to their first winning record since 2019, finishing the year at 16-15 (5-15 Pac-12) with an undefeated 11-0 non-conference record. Under his leadership, three players earned their first career All-Pac-12 awards.
Allen brings experience at the club, high school, collegiate, and adult levels with him to the Cardinal. The author of two coaching books, Coach Your Brains Out: The Art and Science of Coaching Volleyball and The Inner Knight: Train and Compete Like A Champion, Allen is the cohost of the volleyball coaching podcast Coach Your Brains Out.
Outside of coaching, Allen plays professional beach volleyball on the AVP tour. The three-time AVP champion played six years on the USA Beach Volleyball National team, representing his country in competitions around the world.
Allen grew up in Fallbrook, San Diego, and played college indoor volleyball at Cal State Northridge. Allen and fellow AVP player Janelle Ruen, were married in 2009. The two have one son, Ketch.