During the breeding season, Siberian Rubythroats inhabit dense undergrowth, willow thickets along rivers, and subalpine scrub in taiga and tundra-edge environments. In wintering grounds and during migration, they can be found in a variety of habitats including dense scrub, reedbeds, gardens, and cultivation near water, typically at lower elevations.

Spotting a Siberian Rubythroat can be challenging as they are typically shy and prefer to stay hidden within dense vegetation. Birdwatchers should listen for the male's distinctive and often elaborate song, which is a rich, varied, and melodious warble, sometimes incorporating mimicry. Its alarm call is a sharp 'chick' or 'tac'. Patience is key; watch for movement in dense shrubs or at the edge of clearings, especially at dawn or dusk.

These birds are most active during the early morning and late evening. They are present in their breeding grounds from late spring (May) through summer (July-August) and migrate south for the winter, typically arriving in their wintering grounds from September and departing by April. During migration periods, they can be encountered in unexpected habitats outside their typical breeding or wintering ranges.