- Captain Dandy: Welcome to the Outside, Sub Rosa.
- Sub Rosa: It's rather big, isn't it? I can't imagine how you keep it all secure.
PPC Headquarters is filled with plotholes, both stable and unstable. While these are the most common forms of transport between HQ and other worlds, there are also multiple physical doorways connected to HQ.
Each door has a shorthand designation consisting of number-three letters-number.
- The first number is the World designation.
- The letters are the location the door leads to from Headquarters. This usually uses the local language's name for that location.
- Any given location can have multiple doorways. The ending number shows where that particular door lies in the series.
So, for example, Door 1-Cym-3 is a door in World One (1), opens into Wales ("Cym" is an abbreviation of "Cymru," the Welsh name for Wales), and is the third of the HQ doors in World One's version of Wales. Note that there could be more than three doors in World One!Wales, but the existences of 1-Cym-1 and 1-Cym-2 are definite.
The most well known door. The entrance is in an abandoned quarry, and the plateau behind it is riddled with tunnels, some of which are a part of HQ. The camp for the PPC's fighting force during the 2006 invasions was on the World One side of this door.
- Location: Wales (Cymru), England, World One
1-Nou-1 and 1-Nou-2
1-Nou-1 is the door to HQ in the side of the mountain above the PPC city in New Caledonia. 1-Nou-2 is located in the clock tower building in the city center.
- Location: PPC city, Poya, New Caledonia (Nouvelle Calédonie), World One
The Mysterious Somebody and his army entered Headquarters by breaking down this door. It lies near a small, unnamed town. We don't know if this door is functional anymore, after the attack.
- Location: unknown town, Switzerland (die Schweiz), World One
This seems to be the Potterverse analogue of door 1-Cym-3, and was inadvertently reported with the World One numbering. A group of agents and recruits regained access to HQ through this door after their remote activator was damaged.
The tilde seems to reflect the fact that this door leads to an alternate version of World One. It is unknown what the letters "cmb" stand for. Agent Roger Walters joined the PPC after stumbling across this door.