Dominant discourses and practices in international cooperation have been characterised by depoliticisation and unequal power relationships. However, a number of more transformative experiences of cooperation also exist, where joint work between Northern and Southern social organisations is linked with a more political perspective. These kinds of experiences can be considered processes of informal learning in social action: through shared actions, strategies and frameworks and through interaction between organisations, institutions and the grassroots, informal and multidimensional learning processes occur in the people and organisations engaged. The study approaches four cases of networks that have linked Spanish and Colombian organisations which promote advocacy and social mobilisation for the defence of human rights in Colombia. The results show that people engaged in the cases experience intense learning processes that are relevant for the construction of solidarities and a radical global citizenship, but that these processes are also replete with limitations, tensions and challenges.