Previous research emphasises congruences between Western Buddhism and environmentalism, with both presented in juxtaposition to overconsumption, hedonic values, and anthropocentric worldviews. Nevertheless, incongruences also occur, including Buddhist tendencies for social disengagement, avoidance of conflict, and disinterest in the non-sentient world. Yet, virtually no empirical data exist on how Western Buddhist environmentalists negotiate tensions arising from combining the two elements. Here, we address this knowledge gap by exploring interview data from 13 Western Buddhist climate activists. We identify four major themes of negotiation: engagement, confrontation, Buddhist praxis and efficacy. Our findings show that Buddhist philosophy and practice often underwent biospheric reformulation, while the intentions, modes and outcomes of climate activism were often approached in terms of compassion and equanimity. Environmentalism was combined flexibly with Buddhism to justify individual emphases, ranging from solitary meditation practice to radicalised collective activism. Moreover, the negotiations were dynamic and featured unresolved tensions, demonstrating that combining the two elements involves major ongoing negotiation. The study findings have implications for understanding interrelationships between the climate crisis, religion, activism and identity work.