Aren’t They The Same?
Although flexibility and mobility are often used interchangeably, they are not the same thing. They are also always working together to create and control motion, so it can be difficult to separate them out.

How Do They Differ?
While flexibility and mobility sound similar, they are inherently different in terms of movement. Flexibility refers to the ability of a muscle to lengthen during movement. It is passive, and stretching is one of the best ways to determine flexibility. Your body type and/or genetics can also determine how flexible you are - there is a reason some people are better at gymnastics than others. The toe-touching example applies here - if you can touch your toes, do a split, or do a backbend, your muscle tissue can stretch the distance required. But mobility is entirely different, it is the ability to control movements through the entire range of a motion. Think about squatting as an example - to have full mobility squatting, your hips and knees have to bend at the proper angles, and your core must work in sync to control your trunk position. Mobility includes a facet of each of these bodily processes; if one is missing, you will not be able to move as effectively, increasing your risk of injury.