Power dynamics among China, India, and Pakistan constitute a central factor in shaping the regional balance of power in South Asia. The strengthening of the China–Pakistan strategic partnership through the China–Pakistan Economic Corridor (CPEC) and cooperation within the Shanghai Cooperation Organisation (SCO) has intensified India’s strategic concerns and broader geopolitical competition. These developments have affected regional security and stability while also influencing trade, energy connectivity, and the distribution of geopolitical influence. The central question of this study is how the SCO, as a strategic platform, has strengthened China–Pakistan cooperation and affected U.S.–China competition, India’s security concerns, and regional stability in South Asia. The study hypothesizes that enhanced China–Pakistan cooperation through the SCO and CPEC has influenced the regional balance of power by increasing Pakistan’s economic dependence on China, relatively reducing U.S. influence, and intensifying India’s strategic concerns. The study aims to examine the role of power dynamics in shaping and transforming strategic relations among China, India, and Pakistan, with particular emphasis on their economic, military, and geopolitical interactions. Methodologically, the research adopts a descriptive-analytical approach and employs Strategic Triangle Theory as its theoretical framework. The findings indicate that strengthened China–Pakistan cooperation through CPEC and the SCO has contributed to changes in the regional balance of power and increased India’s strategic concerns. In response, India has expanded its strategic and military cooperation and strengthened its defense capabilities. Consequently, these dynamics have contributed to intensified strategic, arms, and nuclear competition in South Asia and reinforced the region’s security dilemma.