ABSTRACT This investigation studies the behaviours of wellness tourists in Northern Thailand with a view to summarising their collective preferences and expectations and addressing a significant gap in research on Thai wellness tourism. This will enable tourism businesses to begin tailoring their offerings to meet the specific needs of this market segment. 643 foreign tourists in Northern Thailand responded to a questionnaire concerning their motivations and preferences for wellness tourism activities. The findings reveal that there are clear differences between the behaviours of different nationalities that can be used to inform wellness tourism development in Thailand. This research uniquely contributes to literature in the field of wellness tourism by identifying and analysing the specific preferences and expectations of international wellness tourists in Northern Thailand, a previously underexplored demographic in the context of regional wellness tourism studies. Furthermore, it introduces a comparative analysis of national differences in wellness tourism behaviours, offering insights that can directly influence the strategic development of localised wellness tourism offerings.