Background: Effective communication can play a vital role in societal transformations towards sustainability and biodiversity restoration. However, the complexity and long-term nature of environmental change presents a communication challenge. If not carefully navigated, messages around environmental degradation can lead to audience disengagement and issue fatigue, at a time when motivation, engagement and positive action is required. Methods: In this Conservation in Action piece, we describe the principles of positive communication, which are being adopted by a growing movement of conservation organizations. We support this approach by reviewing evidence on the role of emotions in decision-making from diverse fields such as psychology and communications, paying particularly close attention to the experiences of climate change communicators. Results: Positive emotional experiences, including feelings of hope, collective efficacy, and the warm glow that follows actions aligned with intrinsic values, can play an essential role in sustaining actions that contribute to transformative change. While negative emotions prime specific action tendencies, positive emotions enable creativity, cooperation, and resilience, which are all essential for overcoming the challenging nature of acting on the biodiversity crisis. Conclusions: Communications from conservation researchers and practitioners need to reflect the reality of the biodiversity crisis. While some communications may seek to motivate action through warnings and threats, messages that trigger positive emotions in audiences can help inspire long-term engagement and action. We suggest that this positive communication approach is underutilized. Implications: We present a guide to help those working in conservation convey their messages in ways that are empowering and positive. As the biodiversity crisis intensifies, it is critical that conservation professionals continue to imagine and develop pathways to a better future and communicate with others in society in a way that supports transformative change towards this future.