* Nargor On the second level in the main cave, just up the stairs to the right of the two docked boats and in the room to the right
* Laguna Islands (a.k.a. Turtle Islands) at the center of the first island after the teleport from Meriana.
* Minotaur Pyramid near Darashia, Ground floor, South side. (Tibianews location) (screenshot)
* Four locations in Kazordoon Dwarf Mines, all surrounding the Mine Hub; you can also find one on the surface Tibianews here.
* Drefia, north beach, south of the main building (just east of the ship, Tibianews here).
* Mintwallin, north part of town.
* Cyclopolis, far north-east part of first level.
* Shadowthorn, The mailbox is at the southern part of the elven fortress. Go down to -1 at the Tibianews shown area on the map, you should find the mailbox a few steps north.
* Orc Fort, inside the fort on the main level, all the way to the east (Tibianews here).
* Talahu (also known as Hydra Island) has a mailbox in it's Teleportation Hub
* Formorgar Mines, Just left of the hoist on the second floor of the mines.
http://tibia.erig.net/Mailbox