A Guide to Flanking in 5e, Warrior attacking an enemy knight from the side

Your Complete Guide to How Flanking Works in D&D 5e

Dungeons & Dragons 5th Edition places a heavy focus on combat encounters. As such, player characters and non-player characters often
How does flanking work in 5e? Does it work differently on square vs hex grids? And, why do many Game Masters have a problem with it?
This article goes over 5e’s rules for flanking and explains common questions around how it works.

Let’s first start with going over the basic rules for flanking in D&D 5e.

Rules for Flanking in 5e

Flanking is an optional rule for combat in D&D 5e. When a creature and one of their allies are on opposite sides within 5 feet of an enemy, that creature and their ally have advantage on their attack rolls.

It may come as a surprise that flanking isn’t actually a default rule in D&D 5e. Flanking is an optional ruleset Game Masters can add to their games to give player characters and NPCs a tactical option for engaging in melee combat. You can find the rules for flanking on page 251 of the Dungeon Master’s Guide.

At it’s core, flanking in 5e is a way to get advantage on melee attack rolls. To do this, 2 allied creatures must be standing and adjacent (within 5 feet) to the same enemy on opposite sides or corners if using a grid (which many tables do). Another caveat is neither allied creature can be incapacitated to flank an enemy.

Large and bigger creatures can also flank their enemies. The difference is only 1 of their squares or hexes needs to qualify. For example, a Large creature takes up 4 squares in a 2×2 area, so only 1 square of either square on 1 side of that creature’s space needs to be on the opposite side of an ally to flank an enemy.

And, that’s about it. Those are the basic rules for flanking in 5e:

  • 2 allied creatures must stand adjacent and on opposite sides of an enemy
  • The allied creatures must not be incapacitated

How flank positioning works varies slightly depending on what grid type you use in your games. What’s more, ranged attacks and the reach weapon property introduce slight problems with the ruleset. So, let’s go over these elements of flanking in 5e.

Flanking on a Square Grid

On a square grid, a creature needs to either stand on an opposite side or corner of an enemy from a friendly creature to benefit from flanking.

Squares are possibly the easiest way to determine flanking in 5e. The allied creatures must be on opposite flat sides of a square or on opposite corners.

To determine flanking in 5e, imagine a straight line connecting the centers of the allied creatures. If that line passes through opposite sides or corners of their enemy’s square, then they’re considered flanking and have advantage on their melee attacks.

Here’s a chart demonstrating valid and invalid flanking positions on a square grid for a Small or Medium creature in D&D 5e:

Examples of flanking against Small and Medium creatures in D&D 5e on a square grid

Now, creature size plays a big role in how flanking works in D&D 5e. Tiny, Small, and Medium creatures are fairly easy; you’re only dealing with a single square. Large, Huge, and Gargantuan creatures introduce more possible squares and it can get a little confusing.

That said, the same basic rules for flanking in 5e apply. If allied creatures are adjacent and standing on opposite sides (any square on those sides) or corners, then they’re flanking the bigger creature. Of course, this means bigger creatures actually have more possible ways of getting flanked on a square grid (something hex grids mitigate, but we’ll get to that in a bit).

A Large creature typically uses a 2×2 square. This means there are 2 squares on either side, giving creatures 2 places to stand on one side and 2 on the other. Basically, it means a Large creature could be flanked by up to 12 creatures (counting corners) instead of 8 compared to Small or Medium ones.

Here’s a chart showing the possible flanking positions against Large (2×2), Huge (3×3), and Gargantuan (4×4) creatures:

Flanking against Large & bigger creatures in D&D 5e on a square grid

Basically, Blue is flanking with Blue, Pink with Pink, Green with Green, and Yellow with Yellow. None of a single color is considered flanking with a different color (so no Blue to Yellow, Green to Yellow, etc).

Of course, remember that Gargantuan creatures can be even bigger, meaning there may be even more possible positions for flanking.

Flanking on a Hexagonal Grid

Hexes work similarly for flanking in 5e but have a slight modification. Depending on the size of the enemy, a creature and an ally need to have a number of hexes between each other around their target to the benefits of flanking.

For the most part, flanking on a hex grid in 5e works the exact same as a square grid. Trace a line between the allies flanking a creature. If the line passes through opposite sides of that enemy’s hex, then the allies are considered flanking.

Determining flanking on a hex grid is arguably easier than on a square one…for Medium and smaller creatures. For Large and bigger creatures, things get a bit more complicated. Luckily, it’s not so complicated it becomes unwieldly.

For every size of creature, there needs to be an exact number of hexes separating 2 allies attempting to flank an enemy measuring around that enemy. This applies even for Medium and smaller creatures when the straight line rule doesn’t work.

  • Medium & smaller: 2 hexes
  • Large: 4 hexes
  • Huge: 5 hexes
  • Gargantuan: at least 6 hexes

The important thing to remember with flanking on a hex grid in 5e is there needs to be an exact number of hexes by creature size. Any more or less (with the exception of Gargantuan creatures), and 2 allied creatures are not considered flanking.

Here’s a chart showing both valid and invalid positioning for flanking on hexes in 5e:

Flanking examples in D&D 5e on a hex grid

Remember; the other numbers of hexes between 2 allied creatures doesn’t matter. For example, flanking a Large creature means having exactly 4 hexes between the flanking creatures; the remaining 3 don’t matter.

Flanking & Ranged Attacks

One of the core elements for flanking in 5e is that allied creatures need to be adjacent to a creature and the benefit only works on melee attacks. So, ranged attacks don’t benefit from flanking an enemy.

Simple as that.

The rules for flanking in 5e explicitly outline how it only confers advantage on melee attacks. So, even though you can make ranged attacks in melee range, it won’t benefit from the advantage granted by flanking.

Flanking with Reach

Rules as written, a creature and an ally must be adjacent to flank an enemy. As such, attacking from further than that with a melee weapon with the reach property or a trait which extends your reach won’t benefit from flanking.

Weapons with the reach property are basically explicitly excluded the same way ranged attacks are. Of course, you can still attack with a reach weapon while adjacent to a creature, so you can still benefit from flanking. But, your attacks made further than 5 feet away won’t be at advantage from flanking since you aren’t technically flanking the enemy.

The important part here is adjacency. A creature won’t be flanked by 1 ally standing within 5 feet (an adjacent square or hex) and another standing 10 feet away even if the latter has a reach weapon.

So, you can still get the flanking bonus if you’re attacking with a reach weapon so long as you’re standing adjacent to your target enemy. But, you won’t benefit from flanking while attacking with a reach weapon at 10 or further feet away.

Problems with Flanking & Why Some GMs Dislike It

Line of knights engaging in combat

The biggest issue many Game Masters have with D&D 5e’s flanking rules is the "conga line" it can create. Two player characters flank an enemy, then another enemy flanks one of those characters, than another character flanks that enemy, and so on. A second issue is it makes getting advantage on melee attack rolls, diminishing the unique abilities of certain classes.

On the surface, flanking seems like an interesting way to encourage players to think tactically during combat encounters. Even better, if feels like a reward to players for thinking beyond their own characters and using the rules to their advantage.

That said, there are 2 primary problems many GMs have with flanking. The first is the tendency for player characters and monsters to form a chain and stop moving once in place, creating a stagnant battlefield. The second is that certain character abilities become less impactful.

The Flanking Conga Line

First off, some Game Masters not-so-lovingly refer to flanking as a "conga line." Essentially, the situation unfolds like this; 2 player characters flank a monster, let’s go with a goblin. Well, since player characters can flank, why can’t the monsters? So, one of the goblins buddies flanks one of the player characters. Then, another player character flanks that goblin, then another goblin flanks that player character, and so on.

D&D 5e's flanking conga line of death problem

What’s more, once the conga line is in place, that’s typically where movement on the battlefield stops. That is, unless the Game Master encourages movement like environmental hazards or other dangers aside from the monsters. At that point, you have a line of player characters and monsters whacking each other round after round until the end of the encounter.

Many Game Masters, myself included, feel that using 5e’s flanking rules inevitably results in more boring combat encounters. Of course, it’s part of a GM’s job to ensure this doesn’t happen and it’s very easily mitigated through more dynamic battlefields and interesting combat encounters with unique creatures and goals. But, anything short of constantly crafting these dynamic encounters often results in flanking conga line.

Flanking Diminishes Character Abilities

The second issue, and the more damning in my opinion, is that flanking in 5e makes getting advantage on melee attacks much easier. At first glance, this isn’t an issue. But, it can make some class feature irrelevant, essentially negating the uniqueness of some classes.

For example, Barbarians get Reckless Attack at 2nd-level. This lets them decide to make their first attack on their turn at advantage with the trade off that attacks against them have advantage until the start of their next turn. If it’s as easy as stepping to the other side of an enemy as an ally (like the group’s Fighter or Rogue), why would a Barbarian ever elect to use this feature?

What’s more, certain spells become essentially useless when advantage on attacks is so readily easy to get. For example, the faerie fire spell is effectively a waste of a spell slot when you use 5e’s flanking rules in your game.

Of course, there are outstanding circumstances. For example, the party is beset by a large number of enemies and the Fighter or Rogue are busy with their own fights. But, 5e puts a pretty heavy emphasis on dogpiling monsters as the most effective method of engaging in combat.

What’s more, having easy access to advantage through flanking (for both player characters and monsters) means greater chances of critical hits. This means that Paladin will just constantly crit-fish so they obliterate your end-game villain with a super-powered Divine Smite.

Also, consider the Great Weapon Master feat. They give a player character the option to take a -5 on an attack roll to deal +10 damage. The advantage granted by flanking is relatively easy to achieve, so you’ll have the Great Weapon Master using player character constantly taking the penalty and dealing more damage than is typical.

Should You Use D&D’s Flanking Rules?

Whether you use flanking in your game is up to you. If you feel it makes getting advantage too easy and worry about the tactical repetition, you should avoid it. However, if you don’t care or want your player characters and NPCs to have relatively easy access to advantage, by all means, play with it. If you’re unsure, try it out and if it doesn’t work, let your players know and stop using it.

At the end of the day, whether you use D&D 5e’s flanking rules is up to you or your Game Master.

If you’re fine with having advantage be easy to get, don’t mind the possibility of a conga line of death forming, and your players don’t mind the potential of reducing the effectiveness of certain class features or other abilities; feel free to use 5e’s flanking rules.

But, if you’re new to GMing or worry about balance in combat encounters, you may want to skip adding flanking to your game.

Ultimately, I would advise against using 5e’s flanking rules. This goes double if you’re new to running 5e or tabletop role-playing games in general.

It’s an optional ruleset, so I’d argue the game isn’t necessarily balanced around it. You’ll end up with shorter fights one way or the other. If you like running big combat encounters with the player characters vastly outnumbered, you’ll find that the PCs get downed more often due simply to more monsters making more attacks at advantage.

Additionally, it gets harder to balance combat encounters to avoid the conga line of death which tends to form when flanking it used. You can use various methods like shifting environments, ranged enemies, or a goal other than "kill everything," but that requires more experience in creating different combat encounters.

5e Flanking FAQ

Warriors with shields in a line

Does Flanking Give Advantage?

Yes, flanking in 5e grants advantage on melee attacks made by the creatures flanking an enemy.

The important thing to remember is flanking in 5e only grants advantage on melee attacks made by the adjacent, flanking creatures.

Can You Flank a Huge Creature?

Yes, you can flank a Huge-sized creature in 5e. The 2 creatures flanking a Huge enemy simply need to be standing on opposite sides, meaning any of the opposite 3 squares, or corners.

What’s more, flanking Huge creatures on square grids (but not hex grids) is much easier as you have more spaces to stand it to qualify as flanking. All you need to do is draw an imaginary line between 2 allied creatures within 5 feet of a Huge enemy. If that line crosses opposite sides, on any of the 3 possible squares, or corners, then a Huge creature is flanked.

Can Echo Knight Flank?

The effect produced by the Echo Knight’s Manifest Echo feature can not flank an enemy. The echo created by this ability does not count as a creature so it isn’t considered an "ally" for the purposes of flanking in 5e.

Part of the rules for flanking include that an ally needs to be on the opposite side of a creature. For something to be considered an "ally" for the purposes of flanking, they need to be a creature.

The Echo Knight’s Manifest Echo is an ability. It doesn’t describe the echo created as a creature on its own. As such, it doesn’t qualify as an "ally."

Can a Familiar Flank?

Yes, familiars can flank in 5e. They are technically allied creatures and so qualify for the flanking rules outlined in the Dungeon Master’s Guide.

Flanking requires an ally on the opposite side and adjacent to an enemy creature. Since familiars count as creatures and they’re friendly to you, they meet the requirements as an ally.

Does Flanking Trigger Sneak Attack for Rogues?

Yes, a Rogue flanking an enemy with an allied creature may use their Sneak Attack feature.

Technically, Rogues don’t even need the flank an enemy to trigger Sneak Attack. All you need is an ally within 5 feet of your target, not that they need to specifically be flanking.


Summary of Flanking in D&D 5e

That about covers everything you need to know about flanking in 5e.

Flanking is an optional ruleset in D&D 5e’s Dungeon Master’s Guide. When 2 allied creatures are adjacent to and on opposite sides of an enemy, those allied creatures are flanking that enemy and get advantage on melee attacks for as long as they’re flanking. Flanking doesn’t work with ranged attacks or with melee attacks made with weapons with the reach property further than 5 feet away. While many Game Masters don’t like using 5e’s flanking rules because it results in a line of creatures and it reduces the usefulness of some other abilities, some GMs still like using it for more powerful feeling player characters and monsters.

Do you use flanking in your 5e game? Why or why not? Leave a comment below with your thoughts and experience to help fellow GMs out!

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