Creatures of Different Sizes

In most cases, you can move through the space of a creature three sizes larger than you or larger. This means a Medium creature can move through the space of a Gargantuan creature and a Small creature can move through the space of a Huge or Gargantuan creature. Likewise, a bigger creature can move through the space of a creature three sizes smaller than itself or smaller. You still can't end your movement in a space occupied by a creature. Tiny creatures are an exception, just like with sharing a space. They can move through creatures' spaces and can even end their movement there. Similarly, other creatures can move through and end their movement in a Tiny creature's space.