Green coconuts are the same variety as the brown, hairy ones with which you may be more familiar.
Both come from the coconut palm (Cocos nucifera) (1).
The difference lies in the age of the coconut. Green coconuts are young and not completely ripened, while brown ones are fully mature (2).
Green coconuts have far less meat than mature ones. Instead, they’re prized for their refreshing and healthy water (2).
This article reviews green coconuts, including their health benefits and uses.