Thailand’s procurement of the Chinese-built S26T diesel-electric submarine is advancing, with delivery now targeted for late 2028 due to an amended contract that includes Chinese-manufactured CHD620 diesel engines following delays caused by Western export restrictions. Initially contracted for one submarine in 2017, the project faced setbacks primarily linked to Germany’s embargo on engine exports. The submarine is approximately 64% complete, with China providing extended warranty support, technology transfer, and crew training as part of the revised deal. This development underscores Thailand’s efforts to enhance its maritime defense capabilities amid a complex regional security environment and reflects a growing defense partnership with China, highlighting a shift in geopolitical alignments in Southeast Asia.