Our Coaches

Train with the Best

The Diablo Alliance coaching staff includes former USA National Team Members, NCAA National Champions, College and High School All-Americans and current local Varsity High School Coaches. Each of our coaches work hard to focus their attention on the particular skills and disciplines that are appropriate for the level of athlete under their guidance. Our coaches take special interest in both building individual skills as well as team concepts to ensure our athletes progress together and participate at all levels. As water polo is a team sport we encourage group activities both in and out of the pool and coordinate team social activities with each age group team during each session and at tournament weekends.
Below is a listing of our wonderful group of coaches:

Robby Arroyo

Head Coach & CEO

Robby became passionate about water polo at a young age. He has won major water polo events like National Junior Olympics, Champions Cup, CIF-SS D1, CIF-NCS OPEN, MPSF Conference, and many more including with Team USA and Professionally. While in high school he trained with the 1996 Olympic Team alongside his older brother Gavin. Robby has been focused on expanding the sport of water polo for both boys and girls at multiple levels along with hosting local tournament opportunities to aid in the expansion of the sport (CCCA Regional & State Championships, CAL Cup, ODP National Championships, etc.). Below are some of Robby’s water polo accomplishments:

Diablo Alliance Head Coach (2016-Present)
De La Salle HS Boy's Head Coach (2020-Present)
- 2023 HS Boy's Coach of the Year
- 2021 & 2022 CIF-NCS OPEN Division Champions
Acalanes HS, Boy's Head Coach (2018-2020)
- 2019 CIF-NCS D1 Champions
Las Positas College, Head Men's Coach (2015-2019)
Lamorinda Water Polo, Head Coach, 14U Girls (2012-2016)
California State University, Long Beach - Volunteer Coach (2006-2008)
Golden West, Head Coach 18U Boys (2005)
Foothill High School - Assistant Coach, Men's Varsity (2005)
Pinole Valley - Head Coach 18U Boys
USA National Team
- Member of the USA Youth, Junior and National Teams (1992 - 2000)
- USA "Top 16" Swimmer, US Swimming Jr. and Sr. Nationals
Played Professionally in Greece, Spain and Hungary
University of California, Berkeley:
- 4 Year Starter
- MPSF Champion and NCAA Runner Up (2002)
- Team Captain and member of hiring committee for head coach (2002)
Runner-up at Men's Outdoor Nationals, NYAC (2002)
SOCAL, Won several NJO Championships & Inaugural Champions Cup (1987-1998)
Foothill High School, Santa Ana, CA (1994-1998):
- 4 time All American, All CIF SS, All OC County, All League in Swimming and Water Polo
CIF SS Water Polo Player of the Year (1997) & played in 3 CIF Championship Games - Winning in 1995

Catharine von Schwarz Arroyo

Head Coach & COO

Cat has been involved with water polo with water in some way or another since she was 12 years old. The sport has given her so much and she could not imagine what her life would be like without it. Born in Annapolis, Maryland there was not much opportunity for girls playing water polo, so she played with the boys. From there she was recruited to play at UCLA and went on to play with the US Team and was the first American woman to play professionally in Italy. Some of Cat’s water polo accomplishments are listed below:

2010 UCLA Hall of Fame Inductee

As a Coach:

Diablo Alliance Head Coach (2016 - present)
Carondelet High School Head Coach (2018 -present)
USA National Cadet Team Assistant Coach (2016 - present)
Olympic Development Program (2010 - present)
- 11th/12th grade Head Coach, Pacific Zone (2012 - 2017)
- 11th/12th grade Head Coach, Pacific Northwest Zone (2010 - 2012)
Lamorinda Water Polo, Girls Program Director (2012 - 2016)
St. Mary's College, Moraga - Head Coach (2012 - 2016)
Campolindo High School, Assistant Coach (2012 - 2016)
California State University, Long Beach - Head Coach (2006 - 2008)
Los Angeles Water Polo Club (2004 - 2006)
University of California, Los Angeles - Assistant Coach (2003 - 2004)
Golden West College - Assistant Coach

As a Player:

Professionally:
- Rari Nantes Florentina, Florence, Italy (2004 - 2005)
- I.G.M Ortigia, Sircusa, Sicily, Italy (2001 - 2002)
US National Team:
- Senior National Team (1995 - 2003)
- Junior National Team (1990 - 1996)
Collegiate Career:
- Member of UCLA Athletics Hall of Fame (2010)
- 4 time NCAA Champion (1996, 1997, 1998, and 2000)
- University of California at Los Angeles (1996 - 2000)
Club Career:
- New York Athletic Club (2001 - 2013)
- Naval Academy Aquatic Club (1998 - 2001)

Todd Halvorson

Head Coach and Director of Events

Todd has over 22 years of coaching experience and numerous accomplishments to his name. His teams continually finish in the top tier of every tournament and rank as one of the top age group teams in the Nation. In addition he has sent 3 players on to play in the Olympics.

He currently lives in San Ramon with and has two children, Drew and Dylan. His daughter Drew currently plays water polo and UC Santa Barbara and his son plays at California HS.

1997-Present: As a high school coach he has won 5 North Coast Section Championship Titles and 6 EBAL League Titles
2000-13: ODP Head Coach, for 13 years, of the Pacific Zone 8th Grade and Under Girls Olympic Development Program.
2003 – Awarded Coach of the Year by the Contra Costa Times Newspaper
2006 – Awarded Volunteer Coach of the Year by USA Water Polo
2013-15: Women’s Assistant Coach Team USA, Development National Team
2013 – National Champions Junior Olympics Gold Medal 14U
2013 - Bronze Medal 3rd Place in the Nation 12U Coach
2013 – Awarded National Development Coach of the Year by USA Water Polo to the top age group coach in the nation.
2016 – Silver Medal 2nd Place in the Nation 16U Assistant Coach
2016 – Distinguished Coaching Award given out by USA Water Polo