Part of an ongoing series of 5e (2014) Rules notes.  See the end of the post for notes on 5.5e (2024) rules.

So Invisibility is often one of those “DM Bane” spells or abilities.  Sneak past all the guards, unable to be targeted, overhearing all the secrets, scouting out all the ambushes. It can be really annoying, if not an OP way to get around a lot of hard work.

But (spoilers!) in D&D 5e, it’s … useful, but not game-breaking.

The Invisibility Spell:

A creature you touch becomes invisible until the spell ends [Concentration, up to 1 hour]. Anything the target is wearing or carrying is Invisible as long as it is on the target’s person. The spell ends for a target that attacks or casts a spell.

Well, that sounds ominous. Uber-rogues! Hidden assassins! Parties just waltzing through dungeons!

Hmmmm … but what does that really mean?

What does Invisibility mean?

An Invisible creature has the Invisibility condition, defined as:

   An invisible creature is impossible to see without the aid of magic or a spe⁠cial sense. For the purpose of hiding, the creature is heavily obscured. The creature’s location can be detected by any noise it makes or any tracks it leaves.
Attack rolls against the creature have disadvantage, and the creature’s attack rolls have advantage.

I.e.,

• Impossible to see without the aid of magic or a special sense (see below for more detail).
• Heavily Obscured — a Hazard defined as “A Heavily Obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the Blinded condition when trying to see something in that area.”
  • It’s kind of funny to think of Invisibility as bringing an obscuring field (itself invisible) wrapped around you, but for purposes of the Hide action, that’s how it works. Being Heavily Obscured makes it much easier to Hide
  • An attacker is effectively “Blinded” while dealing with such a target (thus attacking at Disadvantage).
• Still detectable by any noise it makes or any tracks it leaves (or any scent it gives off). A fairly common ruling, though not backed by RAW, is that this (under certain circumstances) represents a Disadvantage on Perception checks. Note that being detected doesn’t necessarily change the Disadvantage to attack such a target; in general, it mainly offers the opportunity to attack it.
  • “I have no visual or auditory or olfactory sign that there is anything near me. So I will not start swinging my sword.”
  • On the other hand, “I saw footsteps running through the puddle!” while not making you an easy target, does make your presence known and, potentially, able to be dealt with. “I hear a footstep, I see a splash in a puddle, I smell a familiar perfume — I swing, but I know I am at a Disadvantage.”

It is sometimes observed that being Invisible is different from being (successfully) Hidden. Taking the Hide action entails the other senses that make one perceivable. (But check out the 5.5e info below.)

Looking at PHB 194:

When you attack a target that you can’t see, you have Disadvantage on the attack roll. This is true whether you’re guessing the target’s location or you’re targeting a creature you can hear but not see. If the target isn’t in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target’s location correctly.

And …

When a creature can’t see you, you have Advantage on attack rolls against it.

What does that mean, basically?

• Attack Rolls against an invisible creature have Disadvantage
• Attack Rolls by an invisible creature  have Advantage.

Which is pretty awesome, but is not game-dominating.

The Devil Is in the Details

Delving deeper, the Invisibility spell:

• Requires Concentration. That makes it pretty good for “I will make you invisible, go scout ahead.” Less so for “Here, let me make you invisible mid-battle, as long as I OH MY GOD THE FIREBALL!”
  • Unless you are an Invisible Stalker, where Invisibility an innate condition that doesn’t require Concentration. Such cases will are clearly stated in the rules.
• Ends when an Invisible creature attacks or casts a spell.
  • Prepping for an attack doesn’t drop the Invisibility (we’re not talking Romulan warbirds here)
  • Actually making the attack roll signifies the attack, and drops the Invis (even if it misses).
    • But executing a spell that creates a saving throw result still counts as dropping the Invis, even though there is no attack roll.
    • Readying an Attack doesn’t drop the Invis, but Readying a spell does.
  • For a Rogue, that attack that drops the spell is probably a Sneak Attack, since that gives them Advantage.
  • For a multi-turn spell-casting, starting the spell breaks the Invisibility.

I see you!

So what might counter Invisibility (beyond footprints or being noisy)?

• Blindsight: “A creature with blindsight can perceive its surroundings without relying on sight.”
• Tremorsense: “A monster with tremorsense can detect and pinpoint the origin of vibrations within a specific radius, provided that the monster and the source of the vibrations are in contact with the same ground or substance “
• Truesight: A creature with truesight can, out to a specific range, see in normal and magical darkness, and see Invisible creatures and objects.

In general, the above are either (a) creatures living belowground or in the dark or in the Underdark, or (b) beings of a higher order.

How about magic?

• See Invisibility does what it says on the tin: “see invisible creatures and objects as if they were visible” for an hour.  Similarly, the 10th Level Divination Wizard class feature, “The Third Eye,” giver an option to “See Invisibility: You can see invisible creatures and objects within 10 feet of you that are within line of sight.”
  (Note that a 2020 Sage Advice Compendium defines line of sight (in another context) as requiring being able to see something, leading some people to assert that the Third Eye feature does nothing because it only sees invisible things that are in line of sight. But this is very clearly “that would be within line of sight if they were visible” in meaning, and ruling otherwise is untoward nitpicking of the SA’s statement in a different context.)
• Dispel Magic will work against an Invisibility spell just fine … but you need to be able to target it, meaning (most likely) a Perception roll first, with the caveats above.
• Create Water is also a good sneaky way to be able to perceive an invisible creature, either through raindrops or through puddles.

And, just as a general note, Area of Effect spells are an excellent tactical counter to Invisibility (think “Depth charges vs suspected enemy submarine”).

All right, then what about 5.5e?

In 5.5e, those with the Invisible condition get the following effects:

Surprise. If you’re Invisible when you roll Initiative, you have Advantage on the roll.

Concealed. You aren’t affected by any effect that requires its target to be seen unless the effect’s creator can somehow see you. Any equipment you are wearing or carrying is also concealed.

Attacks Affected. Attack rolls against you have Disadvantage, and your attack rolls have Advantage. If a creature can somehow see you, you don’t gain this benefit against that creature.

Which all seems reasonable, but doesn’t actually define Invisibility —  it almost arguably (and some folk have made the argument) doesn’t really state you can’t be seen.

The Invisibility spell simply conveys the Invisible condition to its target(s), which remains until the end of the spell duration or “immediately after the target makes an attack roll, deals damage, or casts a spell.” Greater Invisibility even lets you do those things and still be Invisible.

The rules on the Invisible condition contain nothing about using other senses (hearing, smell) other than special visual abilities to overcome the Invisibility (it’s implied by still being able to Attack, even at Disadvantage). More importantly, the rules no longer equate Invisibility with being Heavily Obscured, even though the effects (Disadvantage on Attack) are similar. 

The Heavily Obscured description is terse.

You have the Blinded condition while trying to see something in a Heavily Obscured space. 

Though in the “Exploration” section of the PHB, it does get some definition:

A Heavily Obscured area—such as an area with Darkness, heavy fog, or dense foliage—is opaque. You have the Blinded condition when trying to see something there.

The Hide Action notes (emphasis mine):

With the Hide action, you try to conceal yourself. To do so, you must succeed on a DC 15 Dexterity (Stealth) check while you’re Heavily Obscured or behind Three-Quarters Cover or Total Cover, and you must be out of any enemy’s line of sight; if you can see a creature, you can discern whether it can see you.

On a successful check, you have the Invisible condition while hidden. Make note of your check’s total, which is the DC for a creature to find you with a Wisdom (Perception) check.

You stop being hidden immediately after any of the following occurs: you make a sound louder than a whisper, an enemy finds you, you make an attack roll, or you cast a spell with a Verbal component.

This has three interesting implications:

First, if you have the Invisible condition, you don’t need to Hide because all Hide does is give you the Invisible condition. 

Second, while we do not get anything explicit about how to detect a magically Invisible creature with other senses before they attack, do damage, or cast a spell, the Hide guidelines do provide some hints that could be used: a sound louder than a whisper, a suitable Perception roll against you, an attack, or a spell with a verbal component.

Third, the language that Hidden creatures gain the “Invisible” condition: does that mean the See Invisibility spell (“you see creatures and objects that have the Invisible condition as if they were visible”) or Truesight (“you see creatures and objects that have the Invisible condition”) should spot where people are hiding behind trees?  RAW, it seems so, though that hardly appears to be the intent.  Many people have spent a lot of time complaining about this.

But wait, there’s more.  In a box under “Combat” and “Cover,” it discusses Unseen Enemies: 

When you make an attack roll against a target you can’t see, you have Disadvantage on the roll. This is true whether you’re guessing the target’s location or targeting a creature you can hear but not see. If the target isn’t in the location you targeted, you miss.

When a creature can’t see you, you have Advantage on attack rolls against it.

If you are hidden when you make an attack roll, you give away your location when the attack hits or misses.

While that’s sort of focused on more conventionally hidden creatures, it also applies to magical invisibility as well.

Let’s mix it up even more.

In the order of combat rules on Initiative and Surprise, the rules read:

Surprise. If a combatant is surprised by combat starting, that combatant has Disadvantage on their Initiative roll. For example, if an ambusher starts combat while hidden from a foe who is unaware that combat is starting, that foe is surprised.

The term “hidden” isn’t defined anywhere.  Is a person with the Invisible condition (from either a spell or from taking a Hide move) “hidden.” The “Surprise” section of the Invisible condition focuses just on the attacker getting Advantage on Init, not on this additional Disadvantage on Init for the defender.

(More on Surprise here.)

In short, all of this in 5.5e is kind of a mess — things aren’t defined clearly, or where defined are simplified in unhelpful ways. The 5e rules had their own messy issues, but 5.5e has only made them, um, messier.

As a result, game tables will almost inevitably have to adopt some sort of house rules (probably borrowing from 5e rules). These could be as simple as defining the term “hidden,” acknowledging that in almost all Surprise situations there will be both Advantage and Disadvantage on Init, and some ground rules for how to actually detect Invisible creatures.  Others might go for more elaborate revisions to the rules set. 

Or, perhaps, we’ll get an improved set of definitions with upcoming source book, Unearthed Arcana, or Sage Advice Compendium.