Although sports tourism has matured as a field, research into the decision-making process determining participation is limited. This paper presents insights from an ongoing grounded theory study examining the behaviours of golf tourists. It focuses on the influence of lifestage, negotiation and compromise on decisions to (i) take trips including a golf tourism element and (ii) include a golf tourism element in family trips. The paper suggests two tiers of decision-making unit (DMU): a Meta DMU, comprising family members, that sets rules of engagement for the scheduling and taking of trips over time; and a Trip DMU, comprising those travelling on a particular trip, that decides the trip detail within the rules of engagement set by the different Meta DMUs to which its members belong. Rules of engagement influence the negotiations and compromises required, and can truncate decision-making processes, particularly for families with a shared sports tourism interest. For golfers whose family members do not play golf, the Meta DMU was shown to influence whether a golf tourism element is allowed on family trips, and determines whether trips without the family are taken, as well as setting further rules of engagement for Trip DMUs, which influence trip details.