Hydrovatus picipennis, is a species of predaceous diving beetle found in India, Sri Lanka, Indonesia, Philippines, China and Thailand.
Body elongated with a typical length of about 3.0 and 4.2 mm and the apex of elytra is distinct. Penis apex is broad, which narrows abruptly to a slender tip. In male, the ridges of stridulatory file is larger, and clearly discernible. Male protarsal claws are not distinctly thickened.