Bag of Holding:

[...] Breathing creatures inside the bag can survive up to a number of minutes equal to 10 divided by the number of creatures (minimum 1 minute), after which time they begin to suffocate. (DMG pp. 153-154)

Cap of water breathing:

While wearing this cap underwater, you can speak its command word as an action to create a bubble of air around your head. It allows you to breathe normally underwater. This bubble stays with you until you speak the command word again, the cap is removed, or you are no longer underwater. (DMG p.157)

Cloak of the manta ray:

While wearing this cloak with its hood up, you can breathe underwater, and you have a swimming speed of 60 feet. Pulling the hood up or down requires an action. (DMG p.159)

Can a creature wear the cap or the cloak and hide inside the bag of holding for an unlimited amount of time (and not just 10 minutes)? I am pretty sure that the cap allows it, while the cloak description does not specify how the breathing process is performed

  • 3
    \$\begingroup\$ I'm curious as to what type of game you are playing that this idea would even occur to you. \$\endgroup\$
    – Dale M
    Jun 5, 2016 at 21:14
  • 3
    \$\begingroup\$ Our Rogue came up with this solution in order to sneak into enemy places \$\endgroup\$
    – firion
    Jun 6, 2016 at 5:13
  • \$\begingroup\$ Also, you should make sure you don't have a bag of devouring \$\endgroup\$
    – User 23415
    Jan 8, 2023 at 22:55

4 Answers 4


Both require you to be submersed in water to work. Now, if you were to fill the Bag of Holding with water first ... I'd say the Manta Ray cloak still doesn't work infinitely, because there's only so much oxygen in the water you can breathe.

The Cap however creates a bubble of air around your head, and doesn't insinuate in any way that the oxygen is taken from the surrounding water.

  • 3
    \$\begingroup\$ you are assuming that the Cape's properties are physical/trasmutation ones (eg giving you the capacity to breath the "oxygen in the water") but one could easily argue it works in a purely mystica/arcane/magical manner and requiring you to be underground is just due to the enchantment's nature. \$\endgroup\$
    – Eldebryn
    Jun 5, 2016 at 17:06
  • \$\begingroup\$ Cape as in Cap or Cloak? Either way, you're absolutely right. But that's what this whole discussion, and game is - assuming things. :) \$\endgroup\$
    – ash
    Jun 5, 2016 at 19:19
  • 2
    \$\begingroup\$ Why do you assume water has oxygen in it? As far as I'm aware, oxygen isn't a thing at all, at least in the default setting. \$\endgroup\$ Aug 1, 2019 at 6:22


The bag of holding contains only enough air for 10 minutes. It does not contain any water.


While wearing this cap underwater

this does not apply.

Nor will this

you can breathe underwater

help you in any way, because you are not underwater.

What would help is an effect alike to the first item, but without the underwater theme.

  • \$\begingroup\$ What if I enclose my head in a bag filled with water, then put the cape on? \$\endgroup\$ Jun 5, 2016 at 13:07
  • 4
    \$\begingroup\$ @Jan If you do the math and look at the weight limit of the bag, and how much water of that volume weighs, you end up bursting a bag by filling it with water. It can hold up to 500 pounds with a volume no greater than 64 cubic feet. What does a cubic foot of water weigh? ~ 62 pounds per cubic foot. \$\endgroup\$ Jun 5, 2016 at 19:37
  • 1
    \$\begingroup\$ @JanDvorak the original item is a Cap not a Cape. But at that point, it is up to the DM. how much of you must be underwater for it to count? does the Cap simply create air? Or does it draw air from the water? And if it draws air from the water, are you any better off that the 10 minutes just sitting in the bag gives you... \$\endgroup\$
    – tzxAzrael
    Jul 19, 2016 at 14:23

Both of these items require your character to be "underwater".

The obvious solution, filling a bag of holding with water, will overload the bag's capacity and cause it to rupture. Even filling a quarter of its volume is too heavy for the bag.

Partially filling it (less than a quarter of the way) might qualify. It depends on your DM's interpretation. How much of your body needs to be submerged for it to count? Is there a depth requirement? Where does the air the items supply come from? If the items draw the air out of the water, with a limited supply of water, are you any better off than the 10 minutes that just sitting the bag would allow you?

An alternate solution seems much more practical. What does your DM think about a pipe poking out of the bag? Would that allow air to pass? The inside of the pipe would arguably prevent the bag from closing entirely. But then you might need a good explanation for the guards as to why there's a pipe sticking out of your bag...


You have to be underwater to use either the cape or cloak.

Cape of water breathing:

While wearing this cap underwater you can speak its command word [...] It allows you to breathe normally underwater. This bubble stays with you until [...] you are no longer underwater.

Cloak of the manta ray:

you can breathe underwater...

Neither of these magic items just gives you an unlimited supply of breathable air. They allow you to breathe underwater. So no, you wouldn't be able to use them to survive inside a bag of holding.

  • \$\begingroup\$ Quibble: The Cap of Water Breathing specifically creates the air for you to breathe, and thus explicitly is an unlimited supply of breathable air. \$\endgroup\$ Mar 21, 2020 at 15:26
  • \$\begingroup\$ Actually, the Cap just creates the Bubble without specifying where the air comes from. It's pretty vague and allows the DM to interpret as they need while still following the description. \$\endgroup\$
    – Nick Brown
    Nov 15, 2022 at 14:33

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