Aiming to address the core challenges in long-distance directional drilling technology, such as difficulties in controlling borehole trajectories and low efficiency in continuous coring, this paper presents the application of Long-Distance Directional Continuous Coring (LDC) technology in Singapore’s HDC3-1 geotechnical investigation project. By optimizing and integrating the Directional Coring Drilling (DCD) process with the NQ wireline coring method, this technology enables simultaneous long-distance directional drilling and continuous coring within target borehole intervals. Compared to traditional investigation techniques, LDC offers advantages including controllable borehole trajectories, continuous sampling, shorter project timelines, lower comprehensive costs, and minimal environmental impact. The successful implementation of this innovative technology in Singapore’s urban rail transit HDC3-1 investigation project has demonstrated its feasibility and practicality, providing enhanced approaches and methodologies for geotechnical exploration.