<p>Amid an increasingly coercive environment in Northeast Asia, driven by the closer alignment of Russia, China, and North Korea, this article examines whether energy minilateralism can transform the declarative solidarity of the U.S.–Japan–South Korea triangle, formalised at Camp David (2023) and reaffirmed in Munich (2025), into an operational shield for regional energy security. Although Japan and South Korea import most of their oil and liquefied natural gas from outside the region, every barrel and cargo must still transit contested Northeast Asian sea-lanes. Drawing on discursive analysis of alliance documents, national strategies, and International Energy Agency data, the study treats energy minilateralism as a governance layer nested within existing alliances, shifting attention from supply volumes to energy-flow politics. The findings are threefold. First, the triangle’s current weakness is neither fuel scarcity nor price volatility but porous maritime, digital, and logistical corridors that adversaries can exploit. Second, a viable minilateral rests on a tripartite division of labour: Washington supplies swing-producer capacity and crisis reassurance; Tokyo and Seoul align policies to harden chokepoints and cyber infrastructure. Third, declarations alone are insufficient; operational credibility demands three concrete pillars: real-time intelligence fusion, corridor-specific contingency protocols, and jointly financed resilient infrastructure, that together move cooperation from promise to practice. The findings indicate that a carefully designed energy minilateralism would not replace multilateral norms but would reinforce them by demonstrating how efficacy and legitimacy can align when governance closely matches those bearing the highest risks.</p>