Bintan Island has experienced two consecutive record-breaking rainfall events that took place on 1-2 and 9-10 January 2021, and devastating floods that caused significant losses. This research studied the events to understand the synoptic conditions in which they occurred and to anticipate future incidents. Hourly rainfall data from the Kijang station and Global Satellite Mapping of Precipitation (GSMaP) were used. OLR (outgoing longwave radiation) was also explored as a proxy of convection. Rainfall measurements showed extreme rainfall during both flood events. Anomalies of moisture convergence were observed in the vicinity of Bintan Island during both events. The two extreme rainfall events were the results of interactions among several synoptic phenomena. The first event was associated with strong cold surges and the Borneo Vortex (BV), while the second event involved a moderate cold surge, the Madden-Julian Oscillation (MJO), and the BV. During both extreme rainfall events, the two BV locations were similar and close to Bintan Island, although their initial locations were different. The first BV was formed in the northern South China Sea and then propagated to the equator, due to the southward vorticity advection associated with a strong cold surge, while the second BV stagnated in the west of Borneo. Information on the important factors that triggered extreme events should be useful to manage the coastal environment for future island development. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.