The carapace is broad, flattened, and roughly hexagonal, with an olive to bluish-green color and a hard chitinous exoskeleton. The carapace width can reach up to 23 cm across the spines, with each side having 9 sharp spines, the longest of which forms a characteristic “wing” or point. Males have bright blue claws and legs, while females have claws tipped with red, especially when mature. The abdomen is narrow and tucked under the thorax in males, and broad and U-shaped in mature females, showing sexual dimorphism. Hindmost legs are flattened like paddles, an adaptation for swimming, a key feature of swimming crabs in the Portunidae family. Males and females differ in abdominal flap shape, claw color, and body size.