# If an enemy moves and provokes an opportunity attack, where are they when the AoO happens?

I was surprised to find no mention of this in the Opportunity Attack rules on d20pfsrd or on the Paizo SRD: if an enemy moves from tile A to tile B and provokes an opportunity attack from me in doing so, are they in tile A or B when I perform the opportunity attack?

This is a minor detail, but pretty significant!

• I'm a mundane human with a sword and threaten squares adjacent to me. If my enemy starts their turn adjacent to me then walks away out of range, do I make an opportunity attack as if they're still in range, or do I lose it because they're too far away?
• I have a spear with a reach of 10 feet, and I can't attack foes in adjacent squares with it. An enemy walks up to me, through my threatened range of 10 feet. When they leave my threatened tile to step up adjacent to me, do I take an opportunity attack as if they're 10 feet away, or do I lose it because they're too close?
• Let's say I'm Gargantuan, and an enemy wants to walk through my range. When they take the movement which provokes an opportunity attack from me, where are they when I make my opportunity attack? (Pretend it's very important: I have an ability that will cast in a straight line and might hit multiple targets or none at all, or I might inadvertently smash a pressure plate, etc)

In all cases, ignore 5-foot steps and pretend my enemy has walked far enough to provoke an opportunity attack.

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also note that those weapons with reach, threaten areas in their reach, so the AOO is occurring at 10 feet away instead of 5, so the weapon actually is capable of striking the enemy. – deltree Jun 12 '13 at 16:40
BTW, one common but simple reason this is important are the wolf trip attacks. Most wolves/dogs/canines get a free trip attempt whenever they make a successful attack. So the square in which they fall is actually a big deal. – Gates VP Jun 12 '13 at 20:47
An important caveat on the free trip from canine attacks is that AoOs are considered to happen BEFORE the provocation, so not only is the square they fall in important, but you should note that the AoO for standing up while threatened does NOT allow you to knock them down again. Your free trip from the AoO goes off while they're still prone (and so does nothing), then they finish standing up after the AoO completes. (A readied action by a wolf companion to bite AFTER they stand, though, can knock them down again - and you can still take the AoO before it, too.) – gatherer818 Jul 11 '14 at 2:52

In all cases, the Attack of Opportunity is resolved in the square in which the provoking action is performed.

In the case of movement, the act of moving out of a threatened square is performed in the threatened square - other squares do not come into play until that part of movement has been resolved.

This is not abundantly clear from the rules on Attacks of Opportunity alone. This is an interpretation I make by

• Observing that this is how it works for non-movement actions that provoke Attacks of Opportunity
• Looking at the Attacks of Opportunity Example, particularly situation #3
• Noticing that the Attack of Opportunity mechanics would be rather dysfunctional if situations as basic as the first one you describe wouldn't allow Attacks of Opportunity.
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Two things worth noting, very relevant to the third case in @JonathanHobbs's question: 1. you can choose not to take an AoO, so if you wanted to wait to make that attack, you could (assuming the target continued to move through your threatened area, i.e. continued to provoke for leaving squares you threaten), and 2. you cannot make more than one AoO for the same "provocation" (so even if you have Combat Reflexes, you could not continue attacking that same character as he continues to move). – KRyan Jun 12 '13 at 20:26
@KRyan I know, a year and a half later, are you still sure about the first situation? If A doesn't take the attack of opportunity against B after B moves, B shouldn't be provoking attacks of opportunity from A for further movement because then B would be provoking multiple attacks of opportunity due to the same event, and that's not a thing. – Hey I Can Chan Mar 23 '15 at 12:35
@HeyICanChan Yes, I do. Otherwise only people who threatened the square you started in could ever have an attack of opportunity off of you. I take the line “Moving out of more than one square threatened by the same opponent in the same round doesn’t count as more than one opportunity for that opponent,” as a special case: it doesn’t count as more than one opportunity for any purpose, but there is a separate provocation for each threatened square that opponent left. You’re just limited to using only one of them. – KRyan Mar 23 '15 at 18:10
@KRyan Wow, man, you're reading doesn't count as to mean actually is? That's a challenging reading, and I appreciate it, even if I disagree. – Hey I Can Chan Mar 23 '15 at 19:42
@HeyICanChan No, I am reading it as never counting as more than one opportunity, even though it would otherwise provoke multiple. Multiple provoking things happen, but only at most one of them can ever count. – KRyan Mar 23 '15 at 19:43

The attack of opportunity occurs before the opponent leaves the square. Otherwise, it would be impossible to strike at an opponent who runs away from you (which is the most common case for attacks of opportunity, and the main case they're supposed to handle).

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Thanks for the answer, Bradd. I'm going to wait a day before I accept an answer. You're right, that would pretty well nerf AoOs. – doppelgreener Jun 12 '13 at 8:47
Ernir probably deserves the accept – he managed to ninja me and provide a more detailed answer! – Bradd Szonye Jun 12 '13 at 8:48