Crocothemis erythraea can reach a length of 33–44 millimetres (1.3–1.7 in). These dragonflies haves a flattened and rather broad abdomen. The adult male scarlet dragonfly has a bright scarlet red, widened abdomen, with small amber patches at the bases of the hindwings. Also the veins on the leading edges of the wings are red. Females and immatures are yellow-brown and have a conspicuous pale stripe along the top of the thorax.
