Ecole Polytechnique is a public, scientific, cultural and professional engineering school. The School's Erasmus+ 2021 project has focused primarily on student mobilities within the Engineering Cycle (two semesters of study or 4-5 month internship), but also, as since 2018, on those for students in the new Bachelor of Science program (one semester of study in the fall) and the new Master of Science and Technology (MScT) programs (internship mobility). Over the course of the project, a greater number of mobilities were supported than initially forecast, including both study and internship mobilities. It should be noted that this achievement was particularly significant given the context of gradual resumption of mobility, following the health crisis, which did not favor long periods abroad. This project therefore made a substantial contribution to promoting internationalization and developing the skills of École Polytechnique students. Against this backdrop, the Erasmus+ project aimed to actively support students during their period of mobility.