Rules FAQ How Do Opportunity Attacks Work In D&D 5E?

An often-misunderstood element of 5E D&D, opportunity attacks allow combatants to strike fleeing combatants before they can leave. An opportunity attack, generally, follows these rules:

• A creature provokes an opportunity attack when it moves out of your reach.
• It uses your reaction for the round.
• It allows you to make a single melee attack with a held weapon or unarmed strike.
• It does not benefit from features such as Extra Attack.
• You must be able to see the creature to make an opportunity attack.
• The attack takes place just before the creature leaves your reach.

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This is the part of a weekly series of articles by a team of designers answering D&D questions for beginners. Feel free to discuss the article and add your insights or comments!

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That first point, which tends to be the one that confuses people, means that if you have a reach of 5 feet (you probably do) and a hostile creature moves from a space within 5 feet of you to a space further than 5 feet from you, you can make an opportunity attack as it leaves the space.

An orc with 5' reach
opportunity attack triggered just before the dotted line is crossed​

Avoiding Opportunity Attacks​

There are a number of ways to avoid opportunity attacks. For example, if a creature takes the Disengage action, its movement doesn’t provoke opportunity attacks at all for the rest of the turn, meaning it can move freely through your reach without threat. Other features, such as the Mobile feat for players, and the Flyby trait on monsters, can allow creatures to avoid opportunity attacks without taking the Disengage action. Features that teleport, such as the misty step spell or the Shadow Step feature of the Way of Shadows Monk, never provoke attacks of opportunity either.

Forced movement also doesn’t provoke opportunity attacks. For example, if a thorn whip spell pulls you out of an ogre’s reach, or you freefall past the reach of a giant spider clinging to a nearby wall, those creatures would not make opportunity attacks against you.

On the other hand, if movement uses your action, reaction, or movement, it is not considered forced, and can provoke an opportunity attack normally. For example, if a dissonant whispers spell causes you to use your reaction to move, and that movement causes you to leave a creature’s reach, that creature would make an opportunity attack against you, even though you didn’t willingly undertake the movement; cruel world, ain’t it?

Reach and Opportunity Attacks​

The Equipment chapter in the Player’s Handbook notes that a weapon with the Reach property increases your reach by 5 feet for the sake of attacks with it, including opportunity attacks. This means that, if you’re wielding a halberd, for example, a hostile creature only provokes an opportunity attack from you when they move from a space within 10 feet of you to a space further than 10 feet from you. Counterintuitively, this means wielding a weapon with Reach may actually limit your options for opportunity attacks, in some cases!

An orc with 10' reach
opportunity attack triggered just before the dotted line is crossed​

Alternatively, if you were wielding a whip (which has the Reach property) in one hand and a dagger (no Reach property) in the other, a creature would provoke an opportunity attack from your dagger when moving from within 5 feet of you to a space more than 5 feet from you. It would also provoke an opportunity attack from your whip when moving from within 10 feet of you to a space more than 10 feet from you. Keep in mind, however, you still only have one reaction, meaning you couldn’t take both of these opportunity attacks.

Opportunity Attack Feats​

A few different feats interact with opportunity attacks, and are listed below. There are a number of class features that interact with them as well, but they come up far less commonly.

Mobile​

This feat foils opportunity attacks in a pretty unique way. With Mobile, when you make a melee attack against a creature, that creature can’t make opportunity attacks against you at all for the rest of your turn. And keep in mind, that’s not “hit” with an attack. You just have to try. This feat can even foil Sentinel, as you’re not using the Disengage action.

Polearm Master​

With the Polearm Master feat, so long as you’re wielding a glaive, halberd, pike, quarterstaff, or spear, you can make an opportunity attack with that weapon when a creature enters your reach with it. So, for example, if you’re equipped with a pike, a creature that moves from outside your reach into a space within 10 feet of you would immediately provoke an opportunity attack from that pike. Amusingly, a creature can avoid this attack by taking the “Disengage” action while moving toward you, and doing so will even bypass Sentinel (as Sentinel only allows you to make opportunity attacks on creatures who attempt to leave your reach by Disengaging). Still, it’s a great way to hold enemies at bay, and the closest thing D&D has to the classic “spear-wall” strategy.

Sentinel​

With the Sentinel feat, your opportunity attacks reduce a creature’s movement speed to 0 on a hit, and even the Disengage action doesn’t prevent you from making opportunity attacks on fleeing targets. Keep in mind this doesn’t prevent features like Flyby, or Legendary Actions that ignore opportunity attacks, from working, as they don’t involve the Disengage action. Furthermore, the special reaction you get from the third bullet point of this feat doesn’t count as an opportunity attack, meaning it doesn’t reduce the target’s speed. Still, pair this with Polearm Master and a polearm with Reach, and wish good luck to whomever wants to try and get past you.

War Caster​

Remember how I said above that an opportunity attack must be a weapon attack? The War Caster feat breaks that rule. With War Caster, you can replace an opportunity attack with a single spell, with a casting time of 1 action, which targets only that creature, such as shocking grasp or hold person. Devious trick, but remember that ranged spell attacks made within 5 feet of a hostile creature are at disadvantage, and the opportunity attack goes off as the creature moves, meaning spells like fire bolt will be harder to hit with if the creature’s moving from within 5 feet of you.

 

[Dessert Nomad]

We did have one campaign where we'd missed the "no forced movement" rule and had two characters in the group with Lightning Lure and Grasping Vine. We had two glorious weeks of slaughtering foes by ping-ponging them back and forth past the melee characters before we realised the error.

Yeah, you need dissonant whispers for the 'force opportunity attacks' shenanigans. Lightning Lure, Thorn Whip, invocated Eldritch Blast, and swarmkeeper Rangers can still have a lot of fun moving people around inside of Spike Growth, however. A Swarmkeeper who takes the druid cantrip fighting style can knock people around for 2d6+5d4 damage a round on his own between the swarm and thorn whip.

 

[Eyes of Nine]

Great article! I'd add a protip: DMs should avoid making opportunity attacks for NPCs - why slow the game down for an optional, clunky rule?

Wait - do you mean NPCs that are on the same side as the PCs? Or by NPC do you mean all opponents? Because I wouldn't do away with OoA entirely, since some key abilities are built around it like Cunning Action.

 

[GMMichael]

Wait - do you mean NPCs that are on the same side as the PCs? Or by NPC do you mean all opponents? Because I wouldn't do away with OoA entirely, since some key abilities are built around it like Cunning Action.

If I were running 5e, all NPCs (including monsters) would skip their OAs. It's just not worth the effort. I'm not sure why (or that) WotC built key abilities around a "mechanic" that they were trying to streamline anyway. For what it's worth, I didn't suggest removing OAs - just avoiding them.

 

[zedturtle]

If I were running 5e, all NPCs (including monsters) would skip their OAs. It's just not worth the effort. I'm not sure why (or that) WotC built key abilities around a "mechanic" that they were trying to streamline anyway. For what it's worth, I didn't suggest removing OAs - just avoiding them.

So all the PCs would be able to back away from the monsters, possibly gaining cover or complete immunity from being attacked (i.e. more movement than the monster and the monster being melee only)? Every round, always?

 

[Azuresun]

Tasty! So any creature that triggers a grapple off its basic attack should be able to do it. I wonder if there are any playable monstrous races that can...

This is why things like Sea Spawn and Vine Blights are great as minions.

 

[GMMichael]

So all the PCs would be able to back away from the monsters, possibly gaining cover or complete immunity from being attacked (i.e. more movement than the monster and the monster being melee only)? Every round, always?

Always is a strong word. And I'll ask that you reread my post, but...

Characters in 5e (as I understand it) can move, attack, and move, as long as their speed allows. Since monsters are also characters, they can pretty easily move toward a PC and attack (Charge ability?) on the round following the PC's OA-free withdrawal. Further, if there's some need to be tactical about it, there's no reason that a monster can't ready an action to hit a PC once it's in range, or ready an action to strike a PC who looks like she might be about to flee.

Those outcomes are significantly better than the PC wanting to flee, but stopping to calculate whether he could survive an OA, then deciding against it, then arguing with the DM about whether one or more creatures in range had already used their reactions for the round, then deciding to stay, just to be forced out of range in the next round, and arguing about whether that provokes an OA (because an ally accidentally forced the movement, not the monster), then being reminded there's a Disengage action...

 

[zedturtle]

arguing about whether that provokes an OA (because an ally accidentally forced the movement, not the monster), then being reminded there's a Disengage action...

There's no basis for argument there. If the monster moved and it wasn't under its own power then it doesn't trigger an OA. Done.

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Let's describe a tactical situation and see what you think about it. We begin a turn with a character with 50 feet of movement and a monster 5 feet away (say the monster charged in but came up short, or maybe made contact with an ally that has now Dimension Door'd away or whatever. Behind the character, about 30 some feet away is a wall that will provide half cover.

As presented (NPCs/monsters skip their OAs, your words) the character can move to the monster, deal melee damage and then move back to behind the wall, gaining half cover (assuming the DM provides a mechanism for getting over the wall, e.g. difficult terrain or an Acrobatics check or whatever).

If the monster always skips OAs, then the player has no decision to make. They move back to the wall and gain the bonus. If the monster follows them, then great. They can use their superior mobility to reengage the monster, never needing to worry about leaving reach, because nothing will happen.

If the monster does make OAs (easily tracked by making a tick on a round tracker or having a status condition marker 'Reacted' or whatever) then the player has a choice. Is the possible damage worth the +2 to AC? The choice makes the game more interesting and more tactical. (Now, of course, if your players are casual and suffer analysis paralysis, then maybe you don't want to make that choice available. But that's a group decision, not a game design decision.)

 

[Philature]

This is very useful information. Looking for more from this series.

 

[Gravenhurst48]

Its funny we are doing these now...but I guess it makes sense giving the changing demographics of the site...and the game.

One practical implication of 5E opportunity attacks: you can move around a single opponent, as long as you don't move away, and not draw one. This is different then in some past editions.

Speaking of past editions...2Es optional book "Combat and Tactics" introduced "Attacks of Opportunity". These were drawn for withdrawing from combat, but also sometimes for other actions, like making an unarmed attack against an armed opponent. Some of this carried over into 3e.

Before that, in early editions of D&D, turning and fleeing melee would give the opponent a free attack. Often at a bonus for striking the fleeing characters rear. (+2 to hit and no shield bonus to AC in "Holmes basic", for example). There was some ambiguity if a fighting withdrawal was possible, though in practice DMs often allowed it.

Ahhh, I wanted to mention this fact!

 

[ad_hoc]

I find as a DM that the mechanics of Attacks of Opportunity result in my players always disengaging to leave an enemy’s threat range so that they never trigger them, I wonder if that’s just the nature of my group or if it is the same for others?

I find that is the instinct of new players. I just tell them that they are wasting their action to do it so the monster gets a full turn's worth of free attacks on you on their turn.

In most cases Disengage is a terrible action.

One thing you can do is have monsters trigger them from PCs to get at weaker PCs or to leave melee for ranged attacks. Let them see how little of an impact it makes.