The maritime shipping sector, responsible for nearly 3% of global greenhouse gas emissions, faces significant regulatory, infrastructural, and economic barriers in its transition toward decarbonization. This study employs a multiple case analysis of the European Union’s emissions trading system, China’s green shipping corridors, and Maersk’s adoption of alternative fuels to examine the challenges of regulatory fragmentation, high costs, and inadequate infrastructure. Findings reveal that policy misalignment, insufficient investment in alternative fuel supply chains, and stakeholder disengagement hinder the industry’s green transition. This study advocates for a globally harmonized regulatory framework, strategic investments in alternative fuel infrastructure, and enhanced stakeholder collaboration. By proposing innovative strategies, such as public-private partnerships and digital compliance mechanisms, this research provides a roadmap for overcoming these barriers and accelerating the adoption of sustainable maritime practices. The insights contribute to global efforts to meet the International Maritime Organization’s 2050 decarbonization targets.