This chapter aims at describing and discussing how a virtual intercultural exchange environment designed through three continents to support the learning and collaborative activities of student-teachers from Brazil, Spain, France, and Taiwan can be used to develop teachers' competencies. Students from four different languages and cultures work together using the medium of English as a Lingua Franca (ELF) to exchange their views on education through collaborative tasks. An in-depth analysis of the above learning environment will be presented, transferring what we gained from the students' experiences into a teacher training proposal. In our specific intercultural exchange context, we will discuss what the tasks are, what they are used for, and how they prove to be essential as emerging practices of reflection and negotiation of intercultural reality when different perspectives interact. This three-continent environment also helps build emerging core educative cultures among future professionals in education for teachers of English or teachers of other disciplines using ELF. In the context of competency-based teacher education, intercultural telecollaboration is viewed as a challenge and as an opportunity for the development of competency-based repertoires of teachers in intercultural communication.