The stork-billed kingfisher is a large bird, typically measuring 25 to 38 cm in length and weighing between 140 and 200 grams. Adult birds have a blue-green back, blue wings and tail and a grey to brown head. The neck and underparts are orange-yellow coloured. It has a very large bill, 18 to 20 cm in length, which along with the small legs, is coral red.

It has a direct, laboured flight and its flight appearance in dominated by its plain blue wings and red bill.

There is no obvious sexual dimorphism in adult birds, although females tend to be larger.

Juvenile birds are similar in appearance to the adult but have narrow dusky fringes on the collar, lower throat and breast, giving it a scaly appearance. They also have buff-green fringes on the upper tail coverts. Juveniles also have a duller bill and less prominent red eye-ring in comparison to the adult.