Tubuca coarctata is a species of fiddler crab found in the western Pacific ocean, including Japan, Taiwan, the Philippines, Indonesia, New Guinea and Australia (in Queensland and the Northern Territory).

[5] These are medium sized fiddler crabs with a carapace of males around 21 mm across.

[2] The clawed limb of adult males is in general orange or light brown with the color continuing onto the top and bottom fingers of the claw and fading to white at the ends.

[5][3][2] Sources from Australia refer to adult males having a white spot at the back of the last walking leg.

[2] A hook like projection at the end of the upper claw is present in males.