School children in Aotearoa/New Zealand have participated in formal learning activities outside the classroom for many years, and over time, these learning opportunities have diversified to include international study experiences. Since parents, caregivers, students, staff, and educational establishments make significant investments in international study tours, knowledge about the longer-term effects of the tours on high school students is needed, especially in a New Zealand context. This qualitative study explores the effects on high school students involved in such experiences, five to 25 years after their tour. This research was positioned in a qualitative paradigm and guided by Charmaz’s constructivist grounded theory to focus closely on participants’ meaning. Two semi-structured interviews were conducted with 16 ex-high school students, to explore the longer-term effects of participating in international study tours. Seven teachers were also interviewed, to add context and valuable insights into the organisation of these study tours. The research findings revealed that high school international study tour experiences had a range of lasting influences on participants. These effects were largely related to the development of a range of life skills that participants reflected were valuable for them as they transitioned into adulthood. For example, individual ‘voyages of discovery’ were closely connected to the sharing of experiences and ‘learning from and with each other.’ The findings suggested that participants’ school groups were influential in the overall experience and enabled the students to ‘learn for life,’ developing important life skills and strategies. These outcomes influenced educational choices and contributed to longer-term employability and career success, ensuring the students were ‘going places’. Furthermore, the findings suggested the responsibilities placed on teachers influenced the design and restrictive nature of the study tours, which conflicted with the students’ ideological expectations of freedom, influencing longer-term travel behaviour. The findings also emphasise the significance of affordability. This research gave a voice, for the first time, to ex-students of study tours, by providing opportunities to reflect on their experience, all offering views that participation in the international tour had made a difference to their life, and the perspectives shared offered important insights into their lived experience. The findings resulted in the development of the theory, “It’s the difference that makes a difference,” which contextualises the international study tour experience and longer-term effects on students, demonstrating what had happened to them, why it had happened, and what it meant to their later life. The theory reflects the different individual and collective experiences of dealing with difference in the process of learning, by depicting the adolescent journey and progression in later life. This thesis makes an important contribution to the wider literature on educational tourism. It provides in-depth insights into the experiences of adult New Zealanders who participated in high school study tours earlier in their lives and provides evidence of the effects on their lives longer-term. The research acknowledges that international study tours are spheres for personal transformation, cultural understanding, and opportunities to define identity, and that longer-term these attributes and life skills are sustained. The data and analysis provide in-depth insights into educational choices, identifying the effects of study tours on formal educational pathways and establishing the rationale for subject choices, which were linked to career aspirations or programmes that incorporated opportunities to travel. They also reveal that international study tours are fundamental in determining the direction of many students’ career choices. The findings reflect the complexities, challenges, and uniqueness of the international study tour experience from both an ex-student’s and teacher’s perspective, highlighting the pressures and practicalities of organising an international study tour, and providing important insights into the significance of affordability. This research was conducted before the COVID-19 pandemic.