Kathleen Sumbillo Dubberstein (born May 8, 1994) is a Filipino-American curler from Wisconsin. A 2014 United States Junior silver medalist, Dubberstein represents the Philippines internationally since 2024.
Dubberstein competed at the United States Women's Curling Championship from 2013 to 2019. She also competed at the United States Junior Curling Championships with her team winning a silver in 2014.
Dubberstein competed for the Philippines at the 2024 Pan Continental Curling Championships Division B tournament. Her team finished fourth losing to Kazakhstan in the Division B bronze medal game. Dubberstein would also skip the Philippines in the women's tournament at the 2025 Asian Winter Games, where the team would finish the round robin with a 4âÂÂ4 record, just finishing outside the playoffs in 5th place.
Her team would return to represent the Philippines the following year at the 2025 Pan Continental Curling Championships Division B tournament, where they would win the event, this time beating Kazakhstan's Angelina Ebauyer 11âÂÂ2 in the gold medal game.
Dubberstein partnered with Marc Pfister for the 2025 Asian Winter Games curling mixed doubles event. They opened their campaign with an upset against the South Korean team, and finished in fourth place with a 5âÂÂ3 record, losing to China 6âÂÂ5 in the bronze medal game.
Kathleen is the daughter of Eva and Steve Dubberstein. She has two sisters, Lani and Annmarie, who are also curlers. She was born in British Hong Kong but considers Portage, Wisconsin as her hometown. She is an alumna of Madison College.