The purpose of this paper is to examine whether and how coalition-building within the Visegrad Group, the Three Seas Initiative and with Germany affects Poland's bargaining success in the European Union's legislative decision-making. Building a coalition is defined as agreeing or presenting a common policy position during negotiations on a given legislative issue. I delineate three hypotheses derived from spatial model theory and rational choice institutionalism, predicting that Poland is more likely to be successful in EU lawmaking when it forms a coalition (has consistent preferences) with the members of the V4, the Three Seas Initiative or Germany. A multiple linear regression is used to empirically verify the above claims on the DEU II dataset. Four conclusions emerge from the analysis. First, Poland achieves higher success in EU legislative negotiations when it builds a coalition with Germany. However, the analysis revealed a strong discrepancy between Poland's and Germany's preferences which makes building mutual coalition seriously impeded. Second, it is beneficial for Poland to enter into a coalition with V4 members. Third, contrary to expectations, building a coalition with the members of the Three Seas Initiative does not bring more legislative gains for Poland.