Thousands of millennia ago, Skull Island was the birthplace of many creatures that had evolved on the island. The most notable of them being a species of giant prehistoric ape monsters that ruled over the island. Centuries later, the Iwi migrated to the island and inhabited it as well, worshipping the apes as gods. However, the predatory Skull Crawlers soon invaded the island and terrorized the Iwi people, taking the role of the apex predators and creating a direct rivalry against the ape super-species that ruled over it. The rivalry between the apes and the Skull Crawlers lasted for centuries, with casualties on both sides. However, the ape super-species became critically endangered until only Kong's parents remained. In a final battle, Kong's mother was able to give birth to Kong, however, his parents were eventually killed in battle, leaving Kong as the last of his kind. Due to the race that had killed his parents and his ancestors, Kong despised the Skull Crawlers and sought to keep them from getting to big, and to keep them in the geysers beneath Skull Island.
On April 7, 1973, Skull Island was discovered via satellite imagery. Monarch official Bill Randa approaches and convinces Senator Willis to allow Monarch to accompany Landsat on a mission to the island with military support before the Russians stumble onto their discovery and go there first.
In 2019, after King Ghidorah defeated Godzilla becoming the new alpha of the Titans numerous reports of Titans leaving their original resting places to come to Ghidorah surfaced including creatures from Skull Island. In the meantime, Kong was ensuring that none of the inhabitants left the island after hearing King Ghidorah's alpha call.
After Godzilla killed Ghidorah becoming the alpha of the Titans again, it was revealed that seismic disturbances were reported on Skull Island, leading to Monarch boosting its forces around the island and theories of the island becoming unstable. It is also reported that numerous Titans were converging on Skull Island.
Skull Island consists of numerous swamps, bamboo forests, mountainous regions, and jungles. Some regions are also very mountainous.