We used accelerator mass spectrometry (AMS) 14 C‐dated sediments of the Holocene basal supratidal flat to upper tidal flat facies in 11 cores on the southern Yangtze delta plain to reconstruct relative sea levels of 8.5–8.0 cal ka BP. Three cores were further AMS 14 C dated and used to examine the evolution of sedimentary geomorphological environments in response to the rapid sea‐level rise during the early to mid‐Holocene. Re...