Trying to find the correct insole or orthotic when you are a runner with flat feet is not easy. There are multiple options to select from. The best orthotic is one custom made by a Podiatrist, but those can run as much as $400, though they are sometimes covered by insurance. There over the counter orthotics which can be purchased which are more inexpensive and can be helpful in your treatment. Below I have listed what I believe to be are the best orthotics for a runner with flat feet.
Superfeet– A lot of runners are fans of this orthotic and this orthotic is effective at given cushioning and dissipating force placed on the foot. However, I feel it lacks in giving support and assisting in biomechanical control of your foot.
PowerStep– This is the brand I recommend for most runners with flat feet. It has an EVA top coat to contour to your foot, but still maintains a hard shell to give you the support that you need.