This study provides a comprehensive discussion of changes in the Philippines’ South China Sea strategy under the Marcos Jr. government. Since his election in June 2022, the Philippines has implemented a diversified strategy regarding its South China Sea policy and related disputes with China. In striving for its interests and activities in the South China Sea, the Philippines aims to launch hard and soft checks and balances on China at multiple levels, for example, through multilateral military cooperation with the United States, international arbitration, and applying propaganda tactics. This study attempts to deconstruct the specific actions and overall logic of the Philippines' South China Sea policy by comprehensively analyzing international dynamics and domestic changes. It sheds light on the intricate way global geopolitical contests, particularly the intensifying rivalry between China and the United States, are influencing political sentiment and actions within the Philippines. Concurrently, it examines the Philippines' strategic deployment of its South China Sea policy to catalyze international reactions, such as support from the United States, and how this involves recalibrating its internal political and economic landscape. Overall, the paper shows how the Philippines’ South China Sea policy seeks an optimal balance among various forces while facing many uncertainties and challenges.