Since its announcement in 2015, Nord Stream 2 (NS2) has fueled European public debate about the EU’s role in a multipolar world, the scope and limits of transnational governance, and the trade-off between environment and climate protection vs. economic growth and fossil fuel lobbying. Whereas much has been said and written about the security and military risks issued by the project, the environmental and climate impact of the Russian pipeline has received limited attention. This article analyzes to what extent both institutions and civil societies of the Baltic countries (in particular, those directly involved in the permit process) developed forms of transnational cooperation in order to tackle environmental and climate challenges issued by the planned pipeline. The aim is to contribute to the following research fields: the role of environment and climate in international relations; multiple notions of “security” in the Baltic region; and transnational governance in the face of global challenges. The sources are ENGOs’ publications and statements, official reports as well as media, which are analyzed according to Critical Discourse Analysis.