The collapse of socialist Eastern Europe in 1989 deprived Cuba’s science system of its most important academic peers. To overcome this obstacle and increase its scientific productivity, Cuba drove scientific collaboration with countries in Europe and Latin America. This study explores the role of Cuban scientific collaboration with the U.S. in the absence of diplomatic relations between those countries. The results suggest that Mexico acts as a bridge for increasing scientific collaboration between Cuba and the U.S.—measured as the number of coauthored papers published in WoS and Scopus. When the number of papers co-authored by Cuban academics with their Mexican peers doubled, the number of articles coauthored by Cuban and U.S. scientists in Scopus grew 9.31 times 2 3.22 and 8.11 times 2 3.08. in WoS. The findings support the hypothesis that scientific collaboration favors an increase in the productivity and scientific visibility of countries. Furthermore, the results suggest that scientific collaboration helps to lay bridges between science systems in the absence of diplomatic relations and even in the presence of political and economic hostility between them. Strengthening international scientific collaboration makes it possible for the science systems of developing countries to overcome limitations on resources and carry out cutting-edge research, and also to incorporate their scientists in mainstream research in the areas that promote their technological-scientific development.