Villager trading in Minecraft: professions, workstations, best trades
enchanted Diamond Leggings (19–33 emeralds) and Diamond Boots (13–27) at Expert, Diamond Helmet (13–27) and Diamond Chestplate (21–35) at Master.

The Diamond Helmet is made from five diamonds; it gives 3 armor points and 2 armor toughness and lasts 363 hits. As a helmet, this piece of armor protects your head and is the only one that takes the enchantments for breathing and working under water. This piece works like every other helmet; the Iron Helmet page explains its enchantments.
It is made with the Crafting Table from 5 × Diamond.
5 × Diamond → Diamond Helmet
// Slots with several items cycle through every accepted option.
enchanted Diamond Leggings (19–33 emeralds) and Diamond Boots (13–27) at Expert, Diamond Helmet (13–27) and Diamond Chestplate (21–35) at Master.
At the Crafting Table: 5 × Diamond give 1 × Diamond Helmet. It can be found as loot in Trial Chambers, Bastion Remnant and End City. Sold by Villager: Armorer (Master).
It protects your head and takes Respiration and Aqua Affinity for underwater work. It is an ingredient in one recipe: Netherite Helmet.
363 durability points: each use removes one, and it breaks when none are left. Mending and Unbreaking can extend it.
No: only one per inventory slot.
11 enchantments: Aqua Affinity, Curse of Binding, Blast Protection, Fire Protection, Mending, Projectile Protection, Protection, Respiration and 3 more.
Cover Me with Diamonds (Diamond armor saves lives).