We've beamed you through the security grid. You should be somewhere near the target, but you'll need to look for it.
—Central

It is almost always important to explore a facility to find the locations of the objective room, the exit room, the guards, and to a lesser extent devices like Corporate Safes, and the guard entrances. Exploring a facility allows the player to make strategic decisions about which rooms to visit in which order, how much loot can be acquired safely before high alarm levels, and what route to take to the exit once it is time to leave. Information about the guards' patrols can also support tactical decisions about how to navigate an area safely.

Faster exploration also allows the player to hack mainframe devices more efficiently before their firewalls rise, and exploring more of the facility also gives a direct credit reward if MicroSLAM Apparatus is installed.

The main way to explore a facility is to move agents to see as much of it as feasible.

Hacking Security Cameras helps the player to explore, since hacked cameras give vision to the agency. Cameras can normally only be hacked once they are discovered by seeing them, but a camera can often see parts of a room which are not visible to an agent who can see the camera, especially if the agent is peeking from outside of the room where the camera is.

It becomes more efficient to explore a facility by hacking cameras if you can do so without an agent having direct line-of-sight on the camera. Cameras can also be discovered by Internationale's Wireless Emitter augment or a Wireless Scanner, by hacking a Camera Database, or using the program Oracle. Cameras seen when exploring with a hacked drone can also be hacked to give the agency vision over an area for longer than the drone is controlled, allowing the player to determine the patrols in a room, or whether the room is patrol-free.

Most rooms are rectangular and small enough that a camera in the corner sees the whole room. This means that if you see a camera while peeking through a closed door, there is often no need to spend an extra 1 AP for a full peek with the door open.

Drones can be hacked and temporarily controlled to explore a facility. From mission difficulty 2 onwards, every facility has either a Camera Drone or Pulse Drone, and Sankaku facilities usually also have other drones. While controlled by the agency, drones can be moved by the player, and give full 360° vision to the player with an unlimited range, regardless of their usual vision cone.

Exploring with drones is relatively safer than exploring with agents because hacked drones can step into enemy vision with no consequences, and other guards do not investigate doors opened or closed by hacked drones. However, hacking drones other than Pulse Drones carries some risk, because they become alerted after they return to the enemy's control.

Pulse Drones are the ideal drones to explore with since they are controlled for 2 turns, can move further than other drones, and afterwards they return to their previous patrol due to their Focused AI. Camera Drones are also generally safe to explore with, since they are also controlled for 2 turns, and when alerted they are less dangerous than other drones because they have no weapon. Other types of drone are only controlled for 1 turn when hacked, so it is normally not worth making them alerted just to explore with 6 AP of movement (or less).

The most useful drones to explore with are those near doors which you cannot easily get an agent to. When a drone is patrolling, it may help to wait a turn in order to hack the drone when it is in a different place, in order to explore further with it; when using Parasite, take care in choosing when to infect the drone. At alarm level 1, it is also often advisable to wait so that a drone can remain controlled at the time alarm level 2 is reached; this way its base firewalls will not be raised. However, this should be balanced against the benefit of exploring with the drone to find and hack other devices before their firewalls are raised.

After exploring with a drone, it is usually best to leave the drone rebooting in a place where it will not cause problems for the player. After waking up, drones will be facing in the direction they last moved, and will use their Local Scanner (or Pulse Scanner) for one turn; while rebooting, if they are not in cover then they can also distract other guards, which may or may not be helpful.

Databases can be hacked to reveal information to the player. This information is usually more useful if the Database is found earlier in the mission; the main benefit of hacking them is to see which directions are likely to be dead ends, so the facility can be explored with minimal backtracking.

Every facility has one of the following:

• Hacking a Camera Database reveals the locations of all Security Cameras, including inactive cameras. This allows further exploration by hacking them, and perhaps the opportunity to hack them before their firewalls go up at alarm level 2; even if you don't, their locations can tell you how far the facility layout extends in some directions, and which other directions are likely to be dead ends. This is less useful in K&O facilities, which have fewer cameras than other facilities.
• Hacking a Console Database reveals the locations of all Consoles. This can tell you how far the facility layout extends in some directions, and which other directions are likely to be dead ends. Consoles with low base PWR can also be used to find the exit.
• Hacking a Facility Database reveals the outline of the whole facility layout, giving almost perfect information about dead ends. Additionally, small “dents” in the outline indicate where the exit is, as well as guard entrances. By learning the shapes of prefab rooms, the outline can also reveal the locations of objective rooms.

The decor of most prefab rooms can be used to identify objective rooms or the exit room if a few tiles from the room are revealed, for example if you glimpse them through a door opened by a guard. Objective rooms often have distinctive floor colours, markings on the floor or walls, and cover objects; the exit room also has distinctive wall markings next to the exit teleporter itself.

Some mainframe devices continuously make sounds, which can be heard even if the device is not revealed to the agency; the sounds are louder when the device is nearer to the center of the screen, and quieter when the device is off-screen. By listening for these sounds when exploring, these devices can be roughly located and identified; each device has a distinctive sound.

It may be easier to hear these sounds if you reduce the volume of the game music relative to the game sounds, or play without music.