The breeding range covers southern Siberia, Mongolia, northern, central and eastern China, Korea and Japan.

It winters in north-east India and across South-east Asia to the Philippines and Indonesia, occasionally reaching New Guinea and Australia.

It breeds mainly in reedbeds and can also be found in marshes, paddy fields, grassland and scrub where it forages for insects and other invertebrates.

Oriental reed warblers have small breeding territories and can achieve high population densities.

Major predators at the nest include the Siberian weasel, cats and snakes of the genus Elaphe.