Breathing Underwater [3.P/PF]

[PlusSixPelican]

What are one's options for being able to breathe underwater (or in another environment that's not fond of lungs)? I'd need not every single one, but enough that I can make an economically minded choice.

[Amnestic]

Bottle of Air (http://www.d20srd.org/srd/magicItems/wondrousItems.htm#bottleofAir)/Bottle of Air (http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/a-b/bottle-of-air) is perhaps the most obvious. At 7250gp it might be a wee bit expensive depending on the level though.

There's also Water Breathing (http://www.d20pfsrd.com/magic/all-spells/w/water-breathing).

[Jack_Simth]

Don't forget Alter Self (or Wildshape, or Polymorph, or....) into something aquatic, or the Necklace of Adaptation.

Spell compendium has the Deep Breath spell.

[ShadowFireLance]

Be a Undead or a Construct..No need there...:smallcool:

[Deathkeeper]

Armor of the Deep (http://www.d20pfsrd.com/magic-items/magic-armor/specific-magic-armor/plate-armor-of-the-deep), helm of underwater ACTION! (http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/h-l/helm-of-underwater-action) and Cloak of the Manta Ray (http://www.d20pfsrd.com/magic-items/wondrous-items#TOC-Cloak-of-the-Manta-Ray) all give you water breathing, although they're a bit expensive.
In addition, polymorphing would work. I believe there are lower-level spells in 3.5 that let you turn into other humanoids, so that for Merfolk or Gillmen would work. In PF at least Alter Self does not grant water breathing, although it does give you a better swim speed if applicable.

[molten_dragon]

Adding in a couple more options not already mentioned.

Greater Crystal of aquatic action.
The heart of water spell.
Deepdweller armor property.

[PlusSixPelican]

Alter Self can give me gills?

[Morcleon]

Alter Self can give me gills?

Alter self can get you an aquatic, water-breathing form, which may or may not have gills.

[JeminiZero]

There is also the amphibious +0 LA template from Stormwrack, which give water breathing and swim speed to any humanoid/monstrous humanoid at the cost of -2 Dex. This is great for characters that plan to use heavy armor (e.g. Cleric) since they can afford to dump Dex, and being able to breath underwater removes one of the greatest risks of waddling around in heavy armor.

Stormwrack (and UA) also has a bunch of amphibious races as well.

For those on a tight budget, the Auran Mask (Complete Mage 134) is a one use mundane alchemical item that grants water breathing for 10 minutes at the low cost of 60 gp.

If you expect to be submerged 1/day for a few minutes at most, the Amulet of Aquatic Salvation [MiC] grants water breath for 5 rounds 1/day.

At the mid-end we have the Ring of Water Breathing [MiC], which does exactly what it says for 6k gp.

[subject42]

A single level of Internal Alchemist (http://www.pathfindersrd.com/classes/base-classes/alchemist/archetypes/paizo---alchemist-archetypes/internal-alchemist) will let you hold your breath for one hour per point of constitution.

[Starbuck_II]

Necklace of Adaptation:

http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/m-p/necklace-of-adaptation

Been awesome since 2nd edition. Still good in PF.
Cost: 9K