Astrodactyl resembles a cross between a red pterodactyl and a glider. He has a beak like mouth. His wings are rather small and resemble a glider and are connected to a 'jet pack' like structure on his back. He has large yellow beak, green eyes, black and green clothing on shoulders and waist, green braces around wrists and ankles, and yellow wings.
The Omnitrix symbol is located on his left shoulder.