A character in the party cast Invisibility on herself, making her invisible. She then tried to move past a Giant Spider, which has Blindsight 10 ft. Per "Does Blindsight detect Invisibility?" the Spider can still tell that the character was there, since the rules for Blindsight say "A monster with blindsight can perceive its surroundings without relying on sight"

But, as she leaves the Spider's reach, does the Spider get an Opportunity Attack? Per the rules, "You can make an opportunity attack when a hostile creature that you can see moves out of your reach."

Blindsight just says "can perceive", but an Opportunity Attack requires "you can see". Is the "perceiving" of Blindsight enough to be able to "see" for the purposes of the Opportunity Attack rule?

As the DM, I ruled "no" simply on the principle that "When in doubt, rule in favor of the players", but I'm really not sure that's right, as I may be taking things too literally.


2 Answers 2


Yes, they'd get an Opportunity Attack

Your citation on Opportunity attack requiring a 'creature you can see' does imply sight, but that's a much too literal approach to the answer.

A clarification on blindsight and stealth from Jeremy Crawford on Twitter suggests that blindsight allows you to spot a creature - and would thus trigger the opportunity attack. Note: The invisible creature can choose to attempt to Hide - which would prevent the OA.

Blindsight lets you spot an invisible creature in range, but that creature can still try to hide behind something with Stealth.

While ruling in favor of your PCs is a good idea - there may be times when the opposite could occur (a PC with blindsight wanting an OA.) In this case, the blindsight creature knows exactly where the PC is and that they're leaving - which would trigger the Opportunity Attack.

  • 5
    \$\begingroup\$ I would say that stealth is the super class of not being seen, and addresses more than being seen. Stealth is the ability to be undetected. This includes visually, acoustically, olfactory (don't fart), etc. It's not limited to visual detection. \$\endgroup\$
    – GcL
    Jan 25, 2018 at 0:27

While the strict reading of RAW supports your ruling of no opportunity attack, the choice of naming blindsight implies the opposite.

Mike Mearls apparently agrees with the intent of the naming:

Chris Hopkins (@chopkins779)
‏@mikemearls When a spell/ability says that a creature must see the target, does blindsight/tremorsense count as seeing?

Mike Mearls‏ (@mikemearls)
@chopkins779 yes


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