SRD:5-Foot Step

Excerpt from Action Types

 * In a normal round, you can perform a standard action and a move action, or you can perform a full-round action. You can also perform one or more free actions. You can always take a move action in place of a standard action.


 * If you move no actual distance in a round (commonly because you have swapped your move for one or more equivalent actions), you can take one 5-foot step either before, during, or after the action.


 * A full-round action consumes all your effort during a round. The only movement you can take during a full-round action is a 5-foot step before, during, or after the action. Some full-round actions do not allow you to take a 5-foot step.


 * A 5 ft. step is considered no action and does not provoke an attack of opportunity (see Table: Actions in Combat).

Excerpt from SRD:Miscellaneous Actions
You can move 5 feet in any round when you don’t perform any other kind of movement. Taking this 5-foot step never provokes an attack of opportunity. You can’t take more than one 5-foot step in a round, and you can’t take a 5-foot step in the same round when you move any distance.

You can take a 5-foot step before, during, or after your other actions in the round.

You can only take a 5-foot-step if your movement isn’t hampered by difficult terrain or darkness. Any creature with a speed of 5 feet or less can’t take a 5-foot step, since moving even 5 feet requires a move action for such a slow creature.

You may not take a 5-foot step using a form of movement for which you do not have a listed speed.