Köster Advocaten sponsors the sports association KNBSB, Sport Support Haarlem and various sports clubs, as well Openluchttheater Caprera in Bloemendaal.
Köster Advocaten is a partner and sponsor of Sport Support Haarlem, an organization in and around Haarlem is active in providing information, advice, organization and support of the sport.
Köster Advocaten is a partner and sponsor of the Royal Dutch Baseball and Softball Association.
Köster Advocaten is a sponsor of Hockey Club Bloemendaal.
Köster Advocaten sponsors the Velser Basketbalclub Akrides.
Köster Advocaten is a sponsor of Hockey Red-White in Aerdenhout.
Köster Advocaten is a sponsor of Hockey Club Alliance in Heemstede.