News coverage is crucial in increasing public awareness and encouraging engagement with marine environmental issues. However, there are notable gaps in knowledge regarding reporting on marine pollution. Previous studies often focused on environmental themes but neglected the dynamics of themes and stakeholders within societal contexts. Therefore, this study analyzes the long-term trends and implications of marine pollution in Taiwan's news coverage. A total of 3482 news articles related to marine pollution over the past 20 years were analyzed using qualitative content analysis (QCA) and multiple correspondence analysis (MCA). The results showed that negative news coverage predominated. However, as the government and citizen groups proposed policies and initiatives to mitigate marine pollution, neutral and positive coverage has increased recently. News coverage also highlights the spatial characteristics of marine pollution. Oil pollution primarily occurs in coastal industrial zones and international ports, whereas areas near tourist attractions are more prone to accumulating marine debris. Additionally, this study indicates that differences in the amount of news on various types of pollution lead to distinct attention patterns. Marine oil pollution is an event-driven attention pattern. It usually spikes media attention during significant incidents, further prompting the government to revise emergency plans and related regulations. However, marine debris is a progressive attention pattern. Citizen groups initially spearheaded efforts regarding marine debris, gradually attracting public involvement, gaining media attention, and prompting government action. Overall, news coverage effectively illustrates the evolution of themes and the dynamic interactions among stakeholders related to marine pollution issues.