People with flat feet can tend to be prone to injuries, and hence they need shoes that offer stability. Make sure that the shoes have adequate arch support. Shoes that do not have arch support are not good for flat feet. Your arch needs to be lifted to a regular position.
People with flat feet tend to bend the ankles inward, stressing the knees and feet. Arches help people keep a good landing on the ground.
When you do not have arches, it means that they need to be supplemented. Stability is an important feature in running shoes for a person with flat feet.
When you are choosing a hiking sandal, there are factors that you cannot compromise, such as under sole protection, increased breathability, comfort, durability, and adjustability. The reason why you need to go for open shoes is that closed shoes are uncomfortable. The fact that you might have to use different terrains makes you go for sandals that absorb shock so that you will not feel all the bumps and rocks on harsh surfaces.