The organic carbon accumulation rate in mangrove ecosystem was reported to be important sink of carbon as well as that in boreal peat accumulation. For the estimation of 10 years scale organic carbon accumulation rates at mangrove plantation coastal area, the 210Pb is expected to be suitable for decades scale estimation by its half-life, though it has possibility of bio-/physical- turbation effect in applying 210Pb chronology, especially in Asian mangrove ecosystem where the anthropogenic physical turbation by coastal fishery is vigorous. We studied the organic carbon and 210Pb accumulation rates in subtropical mangrove coastal ecosystems in Japan, Vietnam and Thailand to remove the effect of bio- anthropogenic turbation on organic carbon accumulation. We finally concluded that 210Pb was applicable to estimate organic carbon accumulation rates in these ecosystems. The measured organic carbon accumulation rates using 210Pb in mangrove coastal ecosystems of Japan, Vietnam and Thailand were $0.22 - 6.0$ t-C ha-1 y-1.