Last year, the 5th Internationalization Plan of the Universitat Politècnica de Catalunya (UPC) was approved, which, like the previous ones, has sought to achieve a level of internationalization that impacts all the activities of the university and in this, Erasmus+ plays a fundamental role. In the KA131 project of 2022, a total of 923 mobilities were carried out, both for students and staff of this UPC. Likewise, with the reception of several hundreds of incoming students from other partner universities, as well as academic and administrative staff, many other people from the university community who, for different reasons, cannot carry out a mobility, have been exposed to internationalization; advancing in the "internationalization at home." Individually, participants grow personally, academically and professionally; also developing other skills: learning or improving a language, working as a team, planning, adapting, knowing themselves better, improving or developing other skills, facing unknown situations and, therefore, , get out of the comfort zone and, above all, increase your tolerance, recognize the value of other cultures, and learn about and help promote European values. On the other hand, contacts with peers from partner universities allow us to strengthen contacts, deepen the relationship between the universities, resulting in other activities of the university, such as double degrees, research projects, strategic consortia, collaborations in papers, stays of doctoral students. or co-tutelles (co-supervision) of thesis, etc. Erasmus+ is strategic and the key tool for internationalization. For Teaching and Research Staff (PDI), it enriches their teaching experience, contrasting methodologies, collaborating with academics from other universities and contacting students who come from different institutional cultures. In addition, bonds with colleagues from those other institutions are strengthened; bonds that (as we have been able to verify through the extensive program management experience) are maintained over the years between the institutions. Therefore, Erasmus serves to generate stable and lasting links between academic staff. Finally, for the Technical, Management and Administration and Services Staff ("PTGAS" or, to simplify, "administrative staff"), staff in general with much fewer opportunities to develop their international experience, by promoting the Program among this group the aim is to offer them the opportunity to get to know other universities, contact with colleagues from other countries, learn about other realities, learn good practices from other institutions, value one's own institutional culture and, of course, enrich oneself culturally and linguistically, broaden one's horizons and reinforce one's professional training. In short, Erasmus+ has been and is for our university the main instrument to internationalize the university community; both students and PDI and PTGAS; Erasmus+ is the tool to expand knowledge about other institutions, strengthen ties with them that lead to activities that involve a higher institutional commitment, such as double degrees, or even it is the seed to generate strategic consortia in international networks. More recently, within the framework of the European Universities alliances, in which our university participates through the "Unite!" alliance, Erasmus is (since the first call) the tool with which many of the initiatives of the alliance are put into practice and are carried out. Therefore, the strategic importance of the Erasmus Program is of the highest level; that is why it acquires relevance, significance and results of singular importance in our institution.