Every game mode in Rainbow Six Siege has a team playing offense vs a team playing defense. This section will give you a few tips for playing defense and holding down the fort.
The preparation phase for defense involves various protection measures depending on the Operator you are playing, and it still only lasts 45 seconds. Some Operators like Kapkan can lay traps at doorways, Rook can give the team armor, and Mira can set up two-way mirrors. The thing all Operators have in common is the ability to barricade windows and doorways, and reinforce two sections of breakable walls (only one as a Recruit).
Try to protect the objective as much as possible with barricades and reinforced walls. Limit the reinforced walls to the room the objective(s) is(are) in. Reinforced walls are to prevent enemies from breaking through and ambushing you from any direction. However, the Operators Thermite and Hibana can still bust through steel.
If the objective is located near a hatch from the above room, you might want to run upstairs and reinforce that trap door before anyone breaches it and comes down from above.
The point of barricades on the other hand is to cut your enemy’s line of sight short. If they can see you from down the hall, they can shoot you from down the hall. You can barricade as far out as you like, but you only have a short time to do so.
Other defensive measures vary slightly between Operators. Lay down barbed wire to slow enemies down (great next to traps and near barricades), set up shields, and lay down remote-detonated explosives called Nitro Cells.
Once it’s time for the action phase, set yourself up somewhere and dig in. It’s important to play defense and not go far from the objective. Many times players run outward and leave the objective behind. This allows an easy win if the opposing team storms in and takes out whoever might be remaining! If the enemy team isn’t so ballsy and the time runs out, the team on defense will automatically win. There’s no reason to push forward.
One very overlooked feature is security cameras. All Operators on defense can look at the cameras set around the building by pressing the button shown on the bottom of the screen with the camera icon. Switch between the cameras and spot the enemy Operators to list which character it is for your team. They will also be marked at that location with a red marker for that instant. After a few seconds, the red marker will disappear. The new Year 2 Operator, Dokkaebi, can now hack these security cameras to prevent the team on defense from using them.
Protect the objective until the time runs out or kill the entire enemy team to win. Read more tips about playing each Operator on their own pages.