A swim fin has a footwear made of flexible material to make walking easier and a support which is made of rigid material to provide rigidity. A fin is pivotally coupled to the support so that it can rotate between a locked swim position and a walk position. The support can either be permanently attached to the footwear, or removably coupled to a fitting which is permanently attached to the footwear. Extension devices can be provided so that the swim position can be unlocked from the user's knee, without the user having to bend. The shape of the fin is designed to eliminate overlapping with the other fin when the user is walking.