Vocational educators cross boundaries between practices in schools, colleges and workplaces, renegotiating their identities as professionals in a particular vocation and as educators. In order to support learners to enter the global workforce, they also require opportunities to cross boundaries through international practices. However, opportunities for international and intercultural learning are often limited, particularly for trainee vocational educators. This paper highlights an online collaborative process (COLIGE) designed to develop competencies for global education. The COLIGE process has been evaluated through the lens of boundary crossing. Participants were trainee vocational educators undergoing their professional teaching qualification in Scotland and Finland. Action research was undertaken during this three-year project to explore participants' experiences and evaluate the learning mechanisms observed during the activities. Findings suggest activity though all four learning mechanisms (identification, coordination, reflection, transformation), although they were not universally experienced. Difficulties faced by learners are discussed and point to the potential for transformation of practice without sequential engagement with all learning mechanisms.