Move Action Triggers

Some free actions are triggered by a creature using an action with the move trait. The most notable example is the Attack of Opportunity:

Attack of Opportunity

Actions: Free
Trigger: A creature within your reach uses a manipulate or move action, makes a ranged attack, or leaves a square during a move action that it’s using.

You lash out at a foe that leaves an opening.

The triggering creature must make a defence check vs your weapon skill or be hit by your melee Strike. This Strike doesn’t count toward your multiple attack penalty and your multiple attack penalty doesn’t apply to this Strike.

If the triggering creature is moving, then the attack interrupts its movement, occurring right before the creature moves.

If the defence check is a critical failure and the trigger was a manipulate action then you disrupt that action.

You may make an Attack of Opportunity only once per round and do so at the first opportunity, unless declared otherwise on your turn. Additionally, you may declare on your turn that your opportunity attack will be a grapple attempt.

A creature can avoid provoking an Attack of Opportunity by taking the Step action. Teleportation or being rapidly moved by someone or something else without using your own movement or action also does not provoke an Attack of Opportunity. For example, a creature does not provoke an Attack of Opportunity if an explosion hurls it out of a foe’s reach or if gravity causes it to fall past an enemy. However, slow, uncontrolled movement, such as being shoved does provoke an opportunity attack.

Actions with the move trait can trigger free actions throughout the course of the distance traveled. Each time you exit a square (or move 5 feet if not using a grid) within a creature’s reach, your movement triggers those free actions (although no more than once per move action for a given creature acting). If you use a move action, but don’t move out of a square, the trigger instead happens at the end of that action or ability.

Some actions, such as Step, specifically state that they don’t trigger free actions based on movement.