- "A precious Gerudo heirloom reclaimed from the Yiga. It has the power of withstand Naboris' lightning. Guard it with your life until you can return it to Riju."
- — In-game description
The Thunder Helm is a key item from The Legend of Zelda: Breath of the Wild. It is a piece of head armor that Link obtains after defeating Master Kohga at the Yiga Clan Hideout in the Gerudo Desert. It is a precious Gerudo heirloom traditionally worn by the Gerudo Chief.
The Thunder Helm was an heirloom that Riju inherited from her late mother, the previous chief of the Gerudo tribe. The helm was kept in Riju's place in Gerudo Town, but the palace was attacked by the Yiga Clan, who defeated the guards and stole the helm.
When Link comes to Gerudo Desert to free the Divine Beast Vah Naboris from Calamity Ganon's influence, disguised as a Hylian woman, he learns of the theft. Link needs help from Riju to calm Vah Naboris; because she recognizes Link's Sheikah Slate, she realizes that he is the Hylian Champion and a friend of Lady Urbosa. Her bodyguard Buliara suggests they test him first by having him retrieve the stolen Thunder Helm, since the heirloom is necessary to reach Vah Naboris, who is generating lightning.
Link infiltrates the Yiga Clan Hideout and confronts their leader, Master Kohga. After defeating him, Link obtains the Thunder Helm, which he returns to Riju in Gerudo Town. Riju later guides Link through the sandstorm to the Divine Beast's location, then protects Link from getting electrocuted by Vah Naboris thanks to the Thunder Helm.
After Link frees the Divine Beast Vah Naboris and returns back the Thunder Helm, Riju gives the main quest "The Thunder Helm" to help the citizens of her city. In return Link may borrow the helmet; however, it cannot be dyed or upgraded by Great Fairies to increase its defense.
The following side quests are required to complete "The Thunder Helm", which rewards it back to Link. It cannot be upgraded but grants total immunity to lightning and unlike the "Rubber" armor set, without a set bonus.
- "The Search for Barta" from Liana
- "Medicinal Molduga" from Malena
- "The Mystery Polluter" from Dalia
- "Tools of the Trade" from Isha