Terraria: How to Breath Underwater

Breathing Reed
The Breathing Reed is an item which aids underwater travel. It can be found in Water Chests and Ocean Crates. It can also be used as a weapon. When held, the reed appears above the player and the rate at which their breath meter depletes as well as the rate at which they lose health while drowning is halved. The reed’s tip does not need to be above the surface of the water for this to take effect. Additionally, the breath meter refills as soon as the tip of the reed is outside of water, but not within a block.

Gills Potion
The Gills Potion is a buff potion that lets player breathe water instead of air. This means that when you drink The Gills Potion you need to be underwater or else you will suffocate slowly.

Ingredients When crafting you need to be near of  or 

 Bottled Water

 Coral

 Waterleaf

Ultimate Combo
When combined with fish bowl you can eliminate the effect of suffocating. ( You need to wear fishing bowl in to your armor slot)

 Diving Helmet
The Diving Helmet is an armor piece for the helmet slot. It has a 1/50 (2%) chance of being dropped by  . When equipped, it causes the breath meter to deplete much slower and slows the rate at which drowning damage is taken.

Flipper 

The Flipper is an accessory that allows a player to swim in liquid. With the Flipper equipped in an accessory slot, the player can swim upwards in Water, Lava, or Honey, by pressing ↷ Jump repeatedly essentially allowing unlimited multi-jumps while within liquid. The Flipper is found in  , which are found submerged in water. They can also be found in  and .

Diving Gear 
The Diving Gear is an accessory which allows the user to swim and breathe underwater for an extended amount of time. It combines the functionality of the Flipper and Diving Helmet. Apart from combining the two effects into a single accessory, it does not have other unique properties.

Crafting In order to get diving gear you need to combine  and 

Neptune’s Shell 
Neptune’s Shell is a Hardmode (which means that firstly you need to defeat Wall of Flesh) accessory that aids performance underwater (and in other liquids) by granting indefinite breathing time underwater, swimming via the ↷ Jump key, and eliminating the slow movement speed usually caused by water. Entering water with this accessory equipped transforms the player into Merfolk form. While in this form, the breath meter will not display (nor will it decrease), therefore effectively preventing drowning.

It is dropped by   with %2 percentage. (Classic Mode)