As the number of international students increases worldwide, it is crucial to explore what makes international students feel welcomed at university campuses. The study investigates whether higher rates of participation in extracurricular activities and higher frequencies of contact with ethnically diverse students strengthen the sense of belonging to the university. The questions are examined using the data of a German nationwide panel study of international students. The fixed effects regression results (N = 2,998) show that experiencing a change from less frequent to more frequent participation in extracurricular activities offered by the university increases the sense of belonging to the university. The effect turns non-significant when controlling for contact frequencies, academic integration, and psychological adaption. Increasing contact with German and multi-national students is crucial for developing a sense of belonging to the university. However, the contact frequencies and estimated effects vary by region of origin and instructional language. Recommendations for increasing international students' university belonging are derived from the results.