In the Movie Short, Legend of the Boneknapper Dragon, Gobber tells the history of his interactions with the then-mythical Boneknapper Dragon. His story grows more and more less credible. At one point in his young adulthood, he relates he is stranded on a very small desert island, equipped only with a broom hand attachment. He needed to get to the neighboring larger island (but still not very big), but a large number of Hammerhead Sharks gather around him. He fights his way across the water, and is further attacked by his Boneknapper. A Hammerhead Whale supposedly saves him at the last moment.
These two small sandy islands appear in Gobber's account to be tropical islands. Both have palm trees, which are native to tropical regions. Also the Hammerhead Shark is typically found in temperate and tropical waters. In theory this would not be feasible in the cold North Atlantic. It is possible that Gobber has traveled elsewhere in the world during his younger years.
In the Movie Short, Legend of the Boneknapper Dragon, Gobber tells the history of his interactions with the then-mythical Boneknapper Dragon. His story grows more and more less credible. As an adult of perhaps late 20's or 30's, Gobber is being chased by his Boneknapper. He is only equipped with an egg-beater as an attachment for his missing hand. He flees through very dense forests of bamboo, stops to look at a patch of azaleas, then continues to the apex of an active volcano. He is saved by a Hammerhead Yak emerging from the lava of the volcano.
This land or island has a large, cone shaped active volcano, surrounds by lush vegetation of trees and bamboo. There are also azaleas. Neither bamboo or azaleas are native to Scandinavia. In theory this would not be feasible in the cold North Atlantic. It is possible that Gobber has traveled elsewhere in the world during his younger years, as this location has an Eastern Asia 'feel'.
An unnamed island appears in the companion book To Berk and Beyond in the section called "Survival in the Age of Dragons" when discussing shelter. There is no caption. The section discusses finding shelter when lost in the wild. Timberjacks are mentioned as providing decent shelter when no other is available.
In this short story found in the comic The Legend of Ragnarok, Astrid and Stormfly are stranded on an island that isn't named. The island is forested with some beaches and rocky pools. There is a large pit on the island which is easy to fall into. It is also filled with Smothering Smokebreaths.
In this short story found in the Ultimate Dragon Trainer 's Guide magazine, the Dragon Riders search for a Typhoomerang on an unknown island. The island is covered in grass, some of it very tall, and seems to have no tree cover. There appear to be several cliff areas on this island. Typhoomerangs are known to be native to this island.
Far North, in a frigid mining village, a rather rambunctious “ruby” was found. The miners thought they were rich – until the giant ruby sneezed sparks.
— Dragons: Rise of Berk
In the description for Rubeus, a Groncicle, an unnamed town is mentioned. It is far North and somewhat implied to be very snowy and cold. It is unclear what exactly the inhabitants mine, though Rubeus is mistaken for a Ruby.
This location in the game, School of Dragons, is popularly known as 'Credit Island', as credits for the game are scrolled on a board here. It can be accessed in game through the Settings screen. This location, from very early on in the game's existence, was promising to be a special location, but this has never materialized so far.
The island itself is barren reddish rock, and appears to be a caldera of some sort. There is a mist, fog, or smoke filling the caldera itself, and has mysterious wooden gears rising from it.
In the game, School of Dragons, there are activities called "Stable Quests" that the player can send their dragons on. These quests are meant for the dragons the player has housed in their stables, i.e. not currently active. One Quest, titled "Lurking at the Island", involves an old, shrouded, unnamed island which might have something dangerous there. The fog there is described as "burning". Titan Monstrous Nightmares or sonic dragons (for example, the Thunderdrum) are recommended to send on this Quest to maximize success. The Quest has maximum difficulty and takes a total of 16 hours (from School of Dragons, where the player's Stables are located.
Investigate reports of something dangerous lurking at an ancient, foggy island
In the game, School of Dragons there are activities called "Stable Quests" that the player can send their dragons on. These quests are meant for the dragons the player has housed in their stables, i.e. not currently active. In the Stable Quest called "Field Trip", Phlegma takes children to a nearby island to look at its plants and animals. A multi-headed dragon is needed for best success. The island is unnamed. The quest takes 24 hours.
Phlegma is taking her students on a field trip to a nearby island to study the flora and fauna.
In the game, School of Dragons, there are Northern Lights (or Aurora Borealis) near Icestorm Island. If the player flies toward the Northern Lights, they will end up on a small glacier directly in front of the light phenomenon. There is also a sea fishing spot, which can only be fished from the back of a Gronckle and with the Deep sea fishing pole.
In the game, School of Dragons, Snotlout mentions a "Secret Training Island" during the player Quest "New Student". He has the mineral Sylvite, which he gives to the player to experiment with at the Alchemist's lab. The island itself is not seen or described further.
'Sup? I'm Snotlout master of awesome. Hookfang and I found this sylvite at our secret training island! Cool, huh? It's really rare but I'll let you have it for your experiment. Just remember, you couldn't have done this without me!
In School of Dragons' "Rise of Stormheart" Expansion
This unnamed location appears in the School of Dragons Expansion, "Rise of Stormheart". It is a small barren island on the surface, but underneath and around it in the sea it supports fish, coral, and seaweed. The player is able to swim below the surface and find a cave with air. The cave appears to be buttressed with a spine of a large creature. There is a wrecked ship inside as well. Nikora Stormheart uses this secret cave to stash a crate of Grimora venom, as well as crates of other items.
In the game, School of Dragons, there are activities called "Stable Quests" that the player can send their dragons on. These quests are meant for the dragons the player has housed in their stables, i.e. not currently active. During a Quest, the player is provided a "log" of what their dragon(s) are doing. One entry is "Exploring an island for a place to make a bed for the night ...". This may be followed by another entry indicating the presence of other dragons on the island - "Unidentified wild dragons on the island below ...".