This article aims to fill a gap in existing studies by examining methanol's prospects as a cleaner marine vessel fuel and addressing the industry's challenges in reducing pollution from ship oil. The analysis focuses on methanol as a decarbonization fuel option, following its advantages compared to others through data triangulation that uses both bottom-up and top-down approaches to examine the safety concerns and environmental impacts of methanol. The findings support its use as a promising alternative to conventional marine fuels, considering regulations and safety codes related to low-flashpoint fuels and specifying key safety measures. Also, container vessels (6% of the global fleet) consume 23% of all annual bunker volume and require nearly two-thirds of the global bunker demand, along with liquid bulk tankers and dry bulk carriers. These findings, along with the current regulatory landscape and infrastructure requirements for methanol fuel distribution, pose the greatest challenges to its widespread adoption, despite successes by MAN and Wärtsilä engine manufacturers in offering high-pressure diesel combustion technology engines for burning methanol. This study provides insights that can help ASEAN adopt methanol fuel while complying with emission standards and reducing its environmental impacts.