Based on the account of trade union representatives from the mining sector in Ghana and Mexico, this paper offers a re-reading of the debate on transnational unionism between developing global coalitions and local networks. Trade union strategies are captured under three analytical fields: spaces of transnational unionism, modes of interaction, and frames of reference. The paper's objective is to understand how national trade unions articulate the local and the global, and identify the factors that push and pull them into the transnational space. While trade unions in both countries have undergone a process of union renewal, their transnational strategy differs: Ghanaians are engaged in capacity building and Mexicans in coalition building. Strategies of transnational unionism are shaped by national contingencies. First, the Ghanaian trade union intervenes mainly at the African regional level through education and training programs for the rank and file, while the Mexican trade union is present at both the North-American regional and transnational levels, particularly through solidarity campaigns. Second, while Ghanaians maintain weak ties with other trade unions, the Mexicans are engaged in a wide repertoire of action with the North-American trade unions and international federations. Third, Ghanaians conceive their interests on the basis of a strong clan-based identity and see transnational unionism as a mean to increase their resources, while Mexicans build broader coalitions based upon class identity. In both cases, strategies of transnational unionism go beyond the dichotomy of the local and the global. They are socially constructed, locally embedded and are shaped by the dynamics of the political economy in which the trade unions are rooted and the supranational structures of opportunity available to them.