<p>The prosperity of trade along the Maritime Silk Road during the Ming Dynasty facilitated the use of Chinese copper coins as primary or secondary coins in East Asian and Southeast Asian countries. However, there are few studies on Ming Dynasty overseas trade coins in medieval maritime history and numismatics. This study investigated the alloy compositions and lead isotope characteristics of Ming Dynasty coin samples unearthed from the North Reef in the South China Sea via X-ray fluorescence (XRF) and lead isotope (MC-ICP-MS) analyses. The experimental study revealed that most samples are Cu–Pb–Sn ternary alloys. The Pb isotopes of the samples are consistent with the Pb isotopic signatures of some mines in the SE China region. By combining archaeological background and historical documents, it can be inferred that the raw metal materials of the coin samples came from southeast China, and the coins minted entered the overseas trade network.</p>