In 2024, the United States (US) and Mexico signed Minute 330, to address water scarcity in the Colorado River. Under Minute 330, Mexico committed to creating additional water savings through 2026, complementing conservation efforts by the US Lower Basin states during this period. In this paper, we examine the motivations behind Minute 330, its negotiations, and the state of its implementation to understand how it reflects the US–Mexico cooperative relationship amidst scarcity challenges in the basin. Our research takes a multi-method, qualitative approach that draws on semi-structured interviews with members of the Minute Negotiating Group from both countries and other interviewees with expertise on the post-2000 Colorado River Minute process from federal water agencies, NGOs, and universities, as well as members of US-state water agencies and Mexican water user leaders. We conclude that Minute 330 responded to water scarcity challenges in the basin that could not be addressed through prior minutes while setting an important precedent of cooperation and cross-border collaboration between the two countries amid unprecedented circumstances. These features take relevance in light of the post-2026 process and the need to develop additional regulations to manage the Colorado River both at the binational and the US national scale.