Brain coral, forming massive colonies, usually fairly small. Series are meandroid with deep valleys, and walls commonly have a thin groove along their tops. The septa bear sharp spines.

It is usually a fairly dull greyish colour, or sometimes greenish, and polyps are fleshy.

Its valleys are similar in width to the faviid Colpophyllia, though the colonies do not reach the same large size. The relatively large spines of Isophyllia also contrast with Colpophyllia.

Some may be confused with ‘chunky’ Mycetophyllia.