The Sakhalin Grasshopper Warbler has olive-brown upperparts and a white throat and belly. It uses wetlands, shrubland, and other semi-open habitats, and the species is listed for Sakhalin Oblast.
The sexes have similar plumage. The forehead through the upper back is olive-brown, while the rump and upper tail coverts are rusty brown. A fine gray eyebrow sits above a white throat; the upper breast is gray, and the lower breast and belly are white.
This migratory species is associated with freshwater, shrubland, and semi-open habitats. Oiseaux.net describes it as mainly terrestrial and lists invertebrates as its food type.
An extinction-risk assessment has not been added yet.