Islands are the places in the Monster World which certain kinds of Monsters are located, live, and sing depending on what elements they have. There is currently a total of twenty-six Islands (thirty-five if non-Ethereal IsletMirror Islands included): twenty-three of which have a unique song that is produced by the Monsters who live there and work together. Most Islands are covered with Obstacles, or trees and rocks, that need to be cleared in order to make more space. These trees and rocks will cost Coins () to be removed and Diamonds () to be added back to the Island. As a special note, if the camera is zoomed all the way out from an Island, a face can be seen on the front of it, which is the face of the Island's Colossal, Titan, or otherwise entity-less face.
The player first begins on Plant Island, as it is the only Island unlocked at the start. To navigate between the other Islands, the Map () is used, which is unlocked before Cold Island is bought. Buying Cold Island also frees the restriction on Gold Island and Ethereal Island, and opens up Air Island for purchase. When Air Island is purchased, Shugabush Island becomes available, and Water Island is made purchasable. Water Island then allows for purchase of Earth Island, which allows for the purchase of Fire Haven. All Natural Islands, that is, those that manifest the elements of Plant (), Cold (), Air (), Water (), and Earth (), must be purchased in order after the player begins on Plant Island. The player must be at least level 4 in order to purchase them. The level 4 requirement also extends to the unlocking Gold Island, Ethereal Island, and Shugabush Island.
The completed songs of most Islands may be bought in the Market, as part of the soundtrack.
Almost every Island has a face-like area in its front part. This is because the game's lore treats them as huge ancient Monsters known as "Colossals" or “Titans” that saved the Continent's Lands when it split up.
Every Natural Island is missing one of the five Natural elements (not including the lost element Fire). This means that a monster cannot exist on an island which is missing any of the Monster's elements.
The Dipsters are currently the Monsters that appear on the largest amount of Islands in the game, that being thirteen (Plant, Cold, Air, Water, Earth, Haven, Oasis, Light, Psychic, Faerie, Bone, Ethereal, and Sanctum).
In second place are Mammott, Potbelly, Common Wubbox, and Rare Wubbox, all on ten different islands each (Plant, Cold, Air/Water, Earth, Haven/Oasis, Gold).
Mammott and Potbelly: (Light, Psychic/Faerie, Shugabush, Tribal).
Wubbox and Rare Wubbox: (Ethereal, Wublin).
In third place are Noggin, Toe Jammer, and Epic Wubbox all on nine different islands each (Plant, Cold, Air, Water/Earth, Haven/Oasis, Gold).
Noggin and Toe Jammer: (Psychic/Faerie, Bone, Tribal)
Epic Wubbox: (Ethereal)
In fourth place are Tweedle and Kayna, both of them being on eight different islands (Haven, Oasis, Tribal).
Tweedle: (Cold, Air, Water, Earth, Gold)
Kayna: (Light, Psychic, Faerie, Bone, Amber)
Finally, Quibble, Oaktopus, and Furcorn each are all indigenous to seven different islands (Plant, Cold, Air, Water/Earth, Haven/Oasis, Light/Psychic, Shugabush, Tribal, and Gold).
Some monsters need to be Teleported to, or placed on, certain islands in order to live there:
At the end of the Mythical Island trailer, a sketch of a currently unreleased island is shown, which resembles an early piece of Concept Art for Plant Island.
The Magical Islands are meant to represent the four Outer Islands in Dawn of Fire, with Light Island at Party Island, Psychic Island at Space Island, Faerie Island at Cloud Island, and Bone Island at Cave Island.
Further evidence is the way that they are ordered, as they are ordered in the main menu in the same placements as the Outer Islands.
A possible reason why some monsters are not found on other Islands is because those Monsters cannot adapt to a certain island's climate due to their elements.
Most Islands have a small creature that makes a silent, short appearance on various spots on the island. These spots are usually parts of the Colossal, such as its ears. These small creatures can also appear in the cracks and crevices of an island. These are called Critters.
Unlike in Dawn of Fire, all Islands are made in 2D.