River channel shifting is the geomorphological process involving the lateral movement of an [alluvial](https://en.wikipedia.org/wiki/Alluvial) [river channel](https://en.wikipedia.org/wiki/Channel_(geography)) across its [floodplain](https://en.wikipedia.org/wiki/Floodplain). Koshi river is characterized by high planform dynamics, especially in the lower reaches. We studied the dynamics of channel planform and shifting through systematic analysis and interpretation of diverse channel configurations using multidate satellite images from 1999 to 2019 of the Koshi River from Chatara to the Nepal-India border. Remote sensing techniques and GIS environment was used for change analysis based on imageries of 1999, 2009 and 2019. The channel shifting was determined by assessing and calculating the transient changes in the planform from the temporal satellite data. The result shows that over the stretch of 48 km, the Koshi River is highly braided with no distinct sub-channel observed. Both the river stretch and braiding are greatest within the southern portion compared to the northern part. Between 1999 and 2019, the area of the water channel is reduced by 24.08 km 2 whereas, the channel bars have increased by 68.08 km 2. The river has experienced a clear shift of the channel toward the west in recent years. The average annual rate of shifting was estimated to be 21.6 m year -1 towards the west and 0.8 m year -1 towards the east, with the overall expansion of the river flood plains. Monitoring of river planform helps in effective river management. This result can be utilized for developing integrated river and land management plans in the Koshi basin.