Changewing Island is a nesting ground and home for the Changewing dragons.
"This forested isle hides many surprises in its thick branches — from the acid-spitting, chameleonic Changewings to their iridescent eggs nestled on the boughs. The only safe part of this island is the sky above it, where Changewings are unable to blend into their surroundings. The island is covered in trees, and the Changewings lay their eggs in the branches."
―Hiccup's Map in Race to the Edge
Changewing Island is a dense, forested island, with a thick stream on it. Its coasts are surrounded by precarious stacks of boulders.
The forested island had been discovered by Fishlegs Ingerman and his dragon Meatlug in "Gem of a Different Color". There, they found a "Stone of Good Fortune". However when Fishlegs and his friends decided to return the stone, they realized they were actually dragon eggs. Despite returning the egg, Snotlout Jorgenson and his dragon Hookfang stole four eggs.
Later, the teens go to Changewing Island to study Changewings as part of Dragon Flight Club drill in "Live and Let Fly". The riders then guided wild Changewings that were released by Alvin back to Changewing Island so they didn't head to Berk.
Three years later, the teens went to Changewing Island to search for glowing Changewing acid to light up a new lens they found in "Night of the Hunters, Part 1". They then encountered Tuffwing, a Changewing that Tuffnut managed to capture it get the Changewing acid. Eventually, they used the acid on Snotlout's helmet to power up the Original Dragon Eye.