- “Seek the unknown, Discover the unbelievable, Protect the world's treasure - no matter the peril.”
- ―League moto
Established in the 1920s, the League of Adventurers is a globe-trotting organization dedicated to scientific and archeological studies and expeditions. In 1935, their airship "New Horizons" was driven off course and ended up landing on Adventure Isle, where they would end up establishing friendly relations with the local Arbori tribe. In the time since then, they have established a base at Camp Discovery to explore the caverns and cliffs of the mountains and work on excavating ancient Arbori ruins and have established a rafting expedition course on Roaring Rapids.
Bulletin boards in the League office at Camp Discovery show connections to attractions from other parks around the world and build out their story in general.
In 1931, an archeological team from the League and Indiana Jones discovered the Temple of the Crystal Skull in the Lost River Delta. However, they ran into trouble with the temple's booby traps and had to be bailed out by Doctor Jones.
In 1932, shortly after establishing a submersible program with the submarine "Odyssey", they would embark on an expedition to Atlantis for Whitmore Industries, the first time Preston B. Whitmore would go public with what the 1914 expedition really found down there.
A story detailing the League's efforts to build a climbing trail through the Himalayas to Everest tie into Expedition Everest, with photos revealing the team ran afoul of the attraction's version of the Yeti.