Internal Solitary Waves (ISWs), which are characterized by large amplitudes and strong nonlinearity, are pivotal dynamic phenomena in oceanic processes. These waves contribute significantly to vertical mixing, cross-isopycnal transport of nutrients and sediments, and modulation of marine ecosystems, while posing substantial risks to subsea infrastructures, underwater navigation, and offshore operations. Therefore, a comprehensive understanding of their generation mechanisms, spatiotemporal evolution, and environmental impacts is critical for advancing oceanographic knowledge and ensuring maritime safety. The South China Sea (SCS) and its adjacent regions along the Maritime Silk Road, including the Sulu Sea (Sibutu Passage), Celebes Sea, Lombok Strait, and Andaman Sea, serve as global hotspots for ISW activity because of their complex bathymetry, intense tidal currents, and stratified water columns. This paper synthesizes multidisciplinary advances in ISW research across these regions, leveraging integrated methodologies such as multi-sensor satellite remote sensing (e.g., MODIS, VIIRS, and SAR), in situ observational networks, high-resolution numerical modeling (e.g., MITgcm, FVCOM), and emerging seismic oceanography techniques. Furthermore, the review identifies persistent gaps in knowledge, such as the role of mesoscale and submesoscale processes in wave–current interactions and interference effects between ISWs from multiple sources. Technical challenges, including the assimilation of multi-platform data into predictive models and the development of AI-driven forecast systems (e.g., physics-informed neural networks, convolutional neural networks), are critically assessed. The paper concludes by advocating for coordinated international observational campaigns and next-generation, non-hydrostatic models to unravel the multiscale complexity of ISWs, ultimately enhancing predictive capabilities for scientific and operational applications in these strategic waters.