This study aims to date wooden coffins excavated from graves in Shinnae-dong, Seoul, South Korea, using dendrochronology. The species of woods used to make the coffins were identified as Pinus densiflora S. et Z., one of the major conifers in Korea. Of 12 graves, 10 were successfully dated using various red-pine chronologies of South Korea. Due to the absence of the last-formed tree ring before felling, the number of sapwood rings, used to obtain likely cutting dates, had to be estimated. The terminus post quem for two coffins without plaster frames were AD 1548 and AD 1571, respectively. Eight coffins with plaster frames yielded estimated dates from AD 1664 to AD 1799. The tree-ring dates indicated that the coffins with plaster frames in Shinnae-dong were constructed approximately 100 years later than those without plaster frames.