Many protected areas worldwide are mandated to provide visitor enjoyment and sustainable heritage conservation but face growing challenges and competition. To satisfy modern aspirational markets, parks must design meaningful experiences delivering long-lasting participant benefits that cultivate visitation rates and a conservation constituency. Transformative travel can deliver such benefits through participants' psycho-physiological transformation but market insights critical for experience development in parks are lacking. Our systematic quantitative review of 126 transformative travel articles provides those insights, linking experiential characteristics, participant traits and motivations to experience outcomes according to five transformative travel typologies pertinent to parks: health and wellness, nature-based physical activity, spiritual, cultural and volunteering travel. We identified 35 travel motivations, 14 participant traits and 23 experience characteristics linked to transformation and 28 purposefully or incidentally realised benefits. Transformative travel improved participants' psychological, physiological, social, economic and environmental conditions, as well as satisfaction with and destination loyalty towards parks. Socio-demographic characteristics and propensity for independent versus social travel shaped choice of travel experience. Our results are uniquely conceptualised in a transformative travel framework and transformative market niche model which we apply to sustainable experience development and marketing in parks. We identify implementation possibilities and areas for future research and monitoring.