China’s increasing presence in the Indian Ocean Region, particularly through research vessels like Lan Hai 101 and Shi Yan 6, poses significant challenges for India’s strategic deterrence efforts, especially concerning submarine-launched ballistic missile (SLBM) capabilities. These vessels ostensibly conduct oceanographic surveys but are believed to engage in dual-use activities that enable intelligence gathering on India’s missile tests and submarine operations, thus compromising the operational security of India’s SSBN bastion in the Bay of Bengal. China’s systematic mapping of underwater acoustics and seabed topography enhances its ability to detect Indian submarines, while India’s current capabilities face limitations due to inadequate oceanographic data and numerical deficits in anti-submarine warfare (ASW) assets. As India fortifies its bastion strategy through Project Varsha to shield SSBNs and maintain second-strike credibility, the persistent surveillance from Chinese vessels necessitates urgent enhancements in hydrographic counter-intelligence, ASW technology, and regional cooperation to safeguard its maritime interests and uphold credible deterrence against potential adversaries.