ABSTRACT In this article, we identify and discuss unifying principles to co-design transformational sustainable-tourism interventions through participatory methodologies. We conduct a meta-ethnographic synthesis of the emerging relevant tourism literature (14 articles), and we propose five methodological requirements that underpin effective interventions for sustainable tourism transformations. The requirements are (1) co-creating actionable knowledge, (2) establishing safe spaces, (3) challenging power structures and managing emerging tensions, (4) shaping systemic synergies and (5) blurring the lines. Together, these requirements constitute a modus operandi – that is, a way of thinking and acting collectively that provides a unified foundation for impact-led, practice-oriented research on transformational sustainability in tourism. This modus operandi is a meta-perspective containing a cohesive set of guiding principles that integrate and elevate transformational methods, approaches and techniques, and represents our contribution to accelerating the field’s expansion.