This study aims to trace a historical account of Brazil's journey and its diplomatic stance regarding the hunting, protection, and conservation of whales within its jurisdictional waters. Additionally, it seeks to analyze how these efforts relate to and reinforce other environmental treaties. To achieve these objectives, diplomatic documents, reference works, and academic research on the subject were examined. Document analysis and bibliographic review revealed that Brazil shifted from being a hunting nation to becoming an advocate for whale conservation, driven by the global moratorium on commercial whaling and domestic and international pressures during the 1980s. Starting in 1986, Brazil implemented measures such as the ban on whale hunting, the establishment of marine parks and biological reserves, and the proposal for the South Atlantic Whale Sanctuary to the International Whaling Commission. This Brazilian stance holds the potential for diplomatic synergies with other environmental agreements, such as the United Nations Framework Convention on Climate Change and the Convention on Biological Diversity. Brazil's engagement in whale conservation can serve as a tool of environmental diplomacy. Through cooperation with South American and African countries, Brazil can promote its conservation programs as examples of biological carbon stock restoration, contributing to global efforts to combat climate change and preserve marine biodiversity in the South Atlantic. These actions can bolster Brazil's discourse in international forums and enhance its image as an environmental advocate.