The most practical way to get bigger ankles is to increase the size of muscles and associated tendons of the area by strengthening them. Since ankle muscles are primarily designed for balance, exercises that test the limits of balance are most effective.
Muscles in the ankle
While there are many muscles in the nearby foot and calve, few muscles are found in the ankle. The main muscles are the peroneal longus and peroneal brevis, which can be found along the outside of ankles. Their primary function is to flex the ankle by pushing the front of the foot down and to allow the foot to externally rotate out to the side.
How to strengthen ankles
Ankle muscles can be trained with body-weight resistance or a resistance band. Performing balancing exercises to fatigue will stimulate your peroneal muscles. Balancing exercises can be progressed by completing them with eyes closed or performing them on an uneven surface such as a towel or a wobble board. A resistance band can be placed around the foot to isolate the muscles during dorsiflexion and eversion movements. Resistance bands can be found with different tensions: a beginner should start with a light band, while trained athletes can use medium or heavy bands.