Stricter decarbonization targets force shipping companies to reassess their transition strategy that needs to be economical and compliant with the regulatory targets of the future. This study aims to illustrate the steps that companies may take to achieve these goals for various sizes of container vessels and routes. The decarbonization strategy to be implemented must consider retrofit costs, new shipbuilding prices, efficiencies in new ship design, maintenance, and downtime costs. Through scenario analysis, the study aims to highlight how the decision changes based on the implementation of Carbon Intensity Indicator (CII) and penalties related to the violation of different potential emissions reduction policies. The study reveals that the transition strategies of shipping companies vary based on ship sizes, highlighting the need for tailored approaches in the decarbonization process. The strategies for the same ship size operating on different routes are nearly equivalent. Future fuel price forecasts are crucial in influencing decisions related to ship purchases and retrofits, as economic viability remains a primary concern for the industry. For penalties to be effective in driving change, they must be substantial enough to compel shipping companies to adopt cleaner technologies and fuels. Moreover, clarity on potential future greenhouse gas (GHG) policies and regulations is essential for companies to navigate their decarbonization strategies effectively. The study underscores the complex interplay of environmental regulations, financial considerations, and fuel choices in shaping the decisions of shipping companies for various container vessel sizes.