Adults eat both aquatic and terrestrial invertebrates. Tadpoles probably graze on algae and diatoms along rocky stream bottoms. When disturbed, they dive into the water and take refuge under submerged rocks or sediments. During periods of inactivity, especially during cold weather, individuals seek cover under rocks in the streams or on shore within a few meters of water. Egg clusters are attached to gravel or rocks in moving water near stream margins.
Tadpoles require water for at least three or four months while completing their aquatic development.
Foothill yellow-legged frogs are found in or near rocky streams in a variety of habitats. Terrestrial individuals are primarily diurnal. Frogs may be active all year in the warmest localities, but may become inactive or hibernate in colder areas. Significant seasonal movements or migrations from breeding areas have not been reported. Nussbaum et al.