Rules FAQ How Does Surprise Work in D&D 5E?

The unexpected attack is a common trope in D&D: Ambushes set by goblins to rob travelling merchants; Assassins sneaking into bedchambers to kill a sleeping mark; Treasure chest mimics, waiting to eat the curious and greedy; A doppelganger disguised as an old friend to attack when their target is most vulnerable. In all these situations, you might find someone is surprised once combat is...

The unexpected attack is a common trope in D&D: Ambushes set by goblins to rob travelling merchants; Assassins sneaking into bedchambers to kill a sleeping mark; Treasure chest mimics, waiting to eat the curious and greedy; A doppelganger disguised as an old friend to attack when their target is most vulnerable. In all these situations, you might find someone is surprised once combat is initiated.

mimic - Gui Sommer.png

Mimic by Gui Sommer from Level Up: Advanced 5h Edition


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!

Surprise
Surprise is described in the Player’s Handbook as follows:

Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.
If you’re surprised, you can’t move or take an action on your first turn of the combat, and you can’t take a reaction until that turn ends. A member of a group can be surprised even if the other members aren’t.


Let's run through an example: Claudia the fighter and Sammy the ranger are walking down a dungeon corridor. A pair of bugbears wait hidden in an alcove to ambush them. As Claudia approaches, they leap out and attack!

Step 1. Has anyone failed to notice a threat at the start of combat? (Is anyone surprised?)

Did Claudia and Sammy notice the bugbears? In this situation the bugbears were hiding and the DM rolled Dexterity (Stealth) checks for each of them. Bunion the bugbear got a result of 13 and Krusher the bugbear got a 16.

To determine if the bugbear was noticed, compare the bugbears’ stealth results against Claudia’s and Sammy’s passive Perception.

Sammy has considerable experience with the dangers of dungeon delving, with a passive Perception of 14. As the encounter begins, she’s aware of a creature hidden in the alcove (Bunion). She isn’t aware of all hidden creatures, since she doesn’t perceive Krusher, but Sammy isn’t surprised at the start of the encounter, because she noticed a threat.

Claudia is oblivious with her passive Perception of 9. She is unaware of any hidden creatures, bugbears or otherwise, and before Sammy can warn her, the encounter begins! At the start of the encounter Claudia is surprised.

Step 2. Roll initiative

As a player, announcing your attack first, or surprising the other players and DM in real life, doesn't guarantee your character will attack first. It's up to the DMs discretion. Rules as written, any combat encounter begins with initiative rolls to determine who acts when.

In our example, rolls result in the following initiative order:
  • Bunion the bugbear rolls well and acts first in the initiative order
  • Claudia the fighter goes next
  • Krusher acts third
  • and Sammy acts last due to a bad roll
Step 3. The first round of combat

Unlike previous editions of D&D, in 5E there is no ‘surprise round'. Instead surprised creatures simply don’t get to act or move on the first turn of a combat.

Bunion leaps from the alcove! Moves up to the surprised Claudia and attacks with his morningstar. Having left his hiding place, Claudia sees him, so he makes his attack as normal, (without advantage - in D&D 5E surprised creatures don't grant advantage to attackers). He hits, and due to the Surprise Attack trait (Monster Manual page 33) he deals an extra 2d8 damage! Ouch! Bunion uses the last of his movement to get away from Claudia’s reach. Despite being hit, Claudia is still surprised and can’t take a reaction to make an opportunity attack.

Claudia’s turn is next. She’s surprised! She can’t move or take an action during the first round of combat, and her turn ends. At this point, Claudia is no longer surprised. Now she can take a reaction if the opportunity presents itself, and will be able to act normally on her next turn.

Krusher throws a javelin at Claudia from her hidden position. Krusher is unseen by Claudia so the attack is made with advantage. It’s another hit! Fortunately, Claudia isn’t surprised anymore, and doesn’t take any extra damage from the Surprise Attack trait.

Sammy’s turn is last in the initiative order. She isn’t surprised and can act as usual. She draws her longbow, takes the attack action against Bunion, and moves to take cover in another alcove.

Step 4. Resolve the combat

The rest of the combat is resolved as usual. Being surprised only affects Claudia during her first combat turn. And that’s it!

Like a condition, but not a condition
‘Surprised’
acts like a condition. It alters an creatures capabilities; no actions, movement or reactions, and has a duration specified by the imposing effect; the first turn of combat. However, in 5e it doesn't appear in the list of conditions found in the Players Handbook (Appendix A).

In 4E D&D surprised did appear in the condition list, and also granted attackers advantage against the surprised target. This is not the case in 5E. It's important to recognise that attacking a surprised creature isn't a source of the advantage. But a creature is often surprised by hidden creatures, and being hidden is a source of advantage on attacks.

Once a fight begins, you can’t be surprised again in the same encounter. If another hidden creature enters a combat encounter on a later turn, no one is surprised, although the creature still benefits from being unseen, granting advantage to its attacks.

Any noticed threat? No surprise
A creature is only surprised if it is completely unaware of any threats at the start of the encounter. In an ambush situation, that means if anyone of the ambushing group is detected, the gig is up! On the other hand, "a member of a group can be surprised even if the other members aren’t.” so characters with low passive Perception are more likely to be surprised by ambushes, even if other members of the group aren't surprised.

This tends to favour monsters more than player characters, since groups of monsters are less likely to have as wide a range of ability modifiers to Perception and Stealth. An adventuring group will likely have a character wearing heavy armour, who'll consistently bring the group Stealth score down, likely ruining opportunities to set ambushes. Likewise, using single monster type groups means all the monsters have the same passive Perception, so either all of them will notice a threat, or none will.

In social encounters, in conversation, you'll almost never be able to launch a surprise attack. As soon as you make a move, they'll notice the threat. If however, you've built up trust over time, such as with a long friendly history with someone, you might surprise them with a sudden out-of-character betrayal.

What abilities interact with surprise?
There are abilities which specifically interact with surprise. This isn’t a comprehensive list, but here are some notable examples.

Monster abilities:
  • As mentioned in the example above, bugbears have a trait which deals extra damage to surprised creatures.
  • Creatures with the False Appearance trait (there are many) such as animated objects, mimics, ropers, and treants are undetectable as threats until they move, since they appear to be ordinary objects or parts of the terrains. They are a frequent source of surprise.
  • The gelatinous cube has the Transparent trait which specifies that a creature that enters the cube’s space while unaware of the cube is surprised.
Player abilities:
  • Most notably the rogue subclass Assassin has the 3rd level feature Assassinate which grants advantage against creatures that haven’t had a turn in combat and turns any hit into a critical hit against surprised creatures. Questions about surprise in 5e are almost always prompted by the assassin rogue.
  • A character with the feat Alert can’t be surprised as long as they’re conscious.
  • Although it’s not a specific interaction, the ranger subclass Gloom Stalker 3rd level feature Dread Ambusher (Xanathar’s Guide to Everything) only functions on the first round of combat, so being surprised is particularly bad for gloom stalker rangers, simply by denying them one of their most powerful features.
 

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Will Gawned

Will Gawned

Horwath

Legend
Just roll group check for both parties.

PCs are walking into an ambush, roll group stealth vs highest passive Perception of ambushers,
For ambushers, roll group stealth vs individual PC passive perception.
Ambushers may get advantage on their stealth check if they prepared or picked the ambush sight carefully.
 

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Lyxen

Great Old One
A player can't say for example 'i ready at the start of the other character casting a spell' and then interrupt the spell.

Of course he can ready an action like this, it's just that there are no ways to interrupt a spell casting anyway.

The action happens. And then the reaction occurs.

No, the trigger happens, then the reaction interrupts the turn of whoever is doing the action before it's complete.

I ready an action so that if we are ambushed I attack the ambusher.

Which won't work as you will not see the ambusher (trigger will not be perceivable), and in any case it's not specific enough, see the examples.

To me it sounds like it would make a mess of non-combat scenes.

There is no mess at all. If people suspect treachery, they will just ready an action based on the trigger that seems the most likely to happen.

I have no problem with creativity and immersion in the standard rules. I don't need it promoted by whatever this is.

The standard rules promote nothing of the kind, you can try to immerse and prepare, and everything is wiped out by initiative.
 

ad_hoc

(they/them)
Of course he can ready an action like this, it's just that there are no ways to interrupt a spell casting anyway.



No, the trigger happens, then the reaction interrupts the turn of whoever is doing the action before it's complete.



Which won't work as you will not see the ambusher (trigger will not be perceivable), and in any case it's not specific enough, see the examples.



There is no mess at all. If people suspect treachery, they will just ready an action based on the trigger that seems the most likely to happen.



The standard rules promote nothing of the kind, you can try to immerse and prepare, and everything is wiped out by initiative.

Okay so the Bard readies an action to smash the harp.

And then whatever the PCs do the Bard goes first because it is a reaction and interrupts others no matter what.

That isn't how the reaction rules work. It happens after the action. It doesn't interrupt it.

I think we need a faq on reactions.
 


Or the DM could say "rock falls, everyone dies". so....
What’s that have to do with an interpretation of surprise rules? Oh, maybe the DM yells “surprise!” when the rocks fall? So….

EDIT: point being, when someone wants a loose interpretation of RAW to seemingly benefit the PCs, the same loose interpretation can be used against them.
 
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Careful what you wish for - the DM could then bust out an ambush of always-crit-on-a-hit NPC assassins vs surprised-for-the-whole-combat party members.
Ok. Probably you meant it generally... because it should be obvious, that this is not my wish. In this special case my wish is half a sentence as clarification in the book, not in sage advice.

Generally your advice is good however. Whenever a player (or DM) tries to expoit an unclear rule, you should ask: is it still fun if roles were reversed?
Maybe that generally is a good advice for real life too...
 


Lyxen

Great Old One
Okay so the Bard readies an action to smash the harp.

If what ?

And then whatever the PCs do the Bard goes first because it is a reaction and interrupts others no matter what.

No, reactions interrupt other reactions as well, for example you can counterspell another counterspell.

That isn't how the reaction rules work. It happens after the action. It doesn't interrupt it.

See above.

I think we need a faq on reactions.

From my perspective, there is no need, we have been applying this for years now, both for transitioning to combat and during fights and never had a problem with it.
 

MarkB

Legend
When someone does the first real combat action, we roll for initiative, as per the rules. Those with prepared actions with triggers corresponding to what is really happening are not surprised and get their readied actions when the triggers occur. Those with no actions or triggers that don't occur can be surprised depending on what was visible or not.

For example, treachery during negotiations leads to a sword being drawn and a blow dealt, which some people could have anticipated, but if it's from a hidden assassin, maybe other people (or more likely noone) might have other actions on other triggers.
So, if the triggering action occurs before their turn, do they get to take their readied action and their full turn during the first round?
The danger with this is that it might give too much power in particular to assassins, while rewarding less specific preparedness. I agree that it might be better for some tables, I'm just explaining what works best for us.

Example: discussing with a bard holding a precious harp that we wanted to get, with a few of his friends. I had a spell ready from before approaching them to paralyse the bard if he did anything with the harp. It worked because at some time the bard, out of spite, decided to try and smash the harp to the ground, but if combat had broken out any other way, I would not have been able to get my spell off...
Certainly you would - at least potentially. Since you're there to protect the harp, the bard attempting to destroy it is a hostile action. And since a hostile action is being attempted, initiative is rolled.

If you roll higher than the bard's initiative, you get to try to paralyse him before he smashes the harp on his turn. If you don't, he gets to smash the harp.
 

ad_hoc

(they/them)
If what ?



No, reactions interrupt other reactions as well, for example you can counterspell another counterspell.



See above.



From my perspective, there is no need, we have been applying this for years now, both for transitioning to combat and during fights and never had a problem with it.

"I cast hold person on the Bard"

Sorry the Bard readied an action they smash the harp before you can do anything. No roll.

Counter spell is a specific rule which breaks the general rule. OA is the most obvious one. The OA occurs before the triggering event. That is an exception to the general rule that reactions occur after their trigger.
 

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