Despite what many people think, key limes and regular limes are not the same thing. There are some very noticeable differences between key limes and â€œPersian limesâ€, which are the limes you usually see being sold at the grocery store. Persian limes are usually larger, thicker-skinned, less bitter, and much greener than key limes.
Key limes are usually a lot smaller than regular limes with a thin skin that are sold green for the most part, though they are a bright yellow color when they are ripe. Key limes are also typically much more acidic than Persian limes and have more of a bitter tart flavor than their counterparts.