Maritime search and rescue (SAR) operations are essential for protecting lives at sea. Despite advances in search theory since World War II, SAR missions still suffer from low efficiency and success rates. The IAMSAR Manual, developed by the IMO and ICAO, serves as a global SAR standard, but it primarily assumes open-sea environments and overlooks coastal regions, where most distress incidents occur. Existing SAR theories often ignore the presence of land, limiting their applicability in such areas. This study proposes an improved SAR planning method that modifies the theoretical framework of the IAMSAR Manual to address coastal environments. Specifically, we enhance the computation of the probability of containment (POC) and probability of detection (POD) by incorporating the presence of land into the search area. This enables the derivation of optimal search regions even in complex coastal zones. Numerical experiments demonstrate that the proposed method significantly improves efficiency compared to conventional approaches. The results highlight the need to revise global SAR models to better reflect real-world conditions and provide more adaptable solutions for coastal operations. Our approach contributes to closing the gap between theoretical search models and practical SAR demands, supporting the development of a more comprehensive international standard.