This small-scale narrative study aimed to explore international school (IS) teacher transition in Southeast England (United Kingdom). Through conducting two sets of interviews with eight IS educators, the study examined the experiences IS educators encountered, their perceived needs, and the professional provisions that aided their transition. It considered (a) the stress and coping framework to explain the psychological adjustment and (b) the sociocultural learning paradigm to explain the sociocultural adjustment an individual makes in an IS. The two perspectives were grounded in Lysgaard's U-curve adjustment theory, Maslow's hierarchy of needs, Vygotsky's social constructivism, and Dewey's sociocultural view of experiential learning. The findings indicated that teachers transitioning to ISs had psychological and sociocultural challenges while navigating their transition, and the term 'crossing-over' best described that transition experience. The main challenges educators encountered included a lack of information and communication, navigating culture, and accessing data and information - some challenges began before arriving at their IS. The findings further revealed that participants did not experience any 'honeymoon' stage (suggested by previous research) upon arrival and had positive and negative adjustment periods throughout their first year at their IS. Participants, who were employed at their IS for more than one academic year, had higher levels of positive adjustment during their second year and beyond. The study identified five phases of crossing-over (Predeparture, Upon Arrival, Crossing-over Adjustment, Continuous Crossing-over Navigation, and Departure) and an adjustment line with similarities and differences to what previous studies found. Each of the five phases was associated with a transition timeframe and included personal, professional, and/or cultural considerations. Finally, the study recommends professional provisions to support teachers' crossing-over to an IS. By identifying challenges, needs, and support that may be beneficial for teachers during the five stages of crossing-over, this study makes a novel contribution to the limited literature on teacher transition in ISs.