The Tibian Explorer Society is an elite society of adventurers that explore and research all aspects of Tibia. They are interested in the many different races of creatures, as well as the history of curious structures and items.
The society positions itself where it can be easily accessed by members, but far from the greater metropolis cities. It has outposts in five locations: Port Hope, Northport, Liberty Bay, Svargrond and Yalahar.
Source: https://tibia.fandom.com/wiki/The_Explorer_Society_Quest
Port hope
Npc Explorer Society building in the eastern part of Port Hope.
Liberty Bay
Npc In the eastern part of Liberty Bay, north east from the depot.
Svargrond
Npc Eastern Svargrond, east of Depot
Northport
Npc Explorer's Society post in eastern Northport.
Inner City
Npc Inner City, west side of the main street, north of depot.
Source: https://tibia.fandom.com/wiki/Local_Representative_of_the_Explorer_Society_NPCs