How long does it take sea stacks to be created?

The formation of sea stacks can take thousands to millions of years, depending on various factors such as the hardness of the rock, wave energy, and erosion rates. Initially, coastal cliffs experience erosion from wave action, leading to the formation of caves. As these caves expand and erode further, they can eventually develop into arches. When these arches collapse, the remaining vertical columns of rock become sea stacks.