Sieges are an event very similar to a standard looting event, except the "play area" is much smaller, and the player cannot leave for a specified amount of time. Sieges can happen in these instances:
- When choosing a location to loot, certain areas will put you in a siege
- Randomly on the road, every few days. Normally, a Trader Camp is found before a siege happens.
- During certain events (such as the Golf event).
- Twice in the final day before entering Canada
After a certain amount of time, the player will be notified that the siege is over. Zombies will stop spawning, though any existing zombies will remain. Once the siege ends, the party is able to escape the area by walking off the map, even if they have not killed all of the remaining zombies.
The flashing 'Siege' message will appear and disappear on the top of the screen.
Following the first two sieges (or during your first siege on Deadlier Mode) zombies will crash down through the roof of buildings if you happen to be within one every few seconds,with the amount depending on the Zombie Forecast. The zombies, upon landing, are in a downed state and will take time to get up. Outside of a building, zombies dig their way out of the ground, and they take more time to crawl out rather than immediately falling out of the roof. However, once they are out, they are immediately able to walk and attack.
A normal siege lasts between 50 minutes to 1.5 hours. However, the second to last stage of the Final Siege, lasts 4 hours.
- Hoard ammunition for powerful firearms which may be collected from safes in looting locations or bought from Traders. These and chainsaws can be extremely helpful in case you get cornered or need to rescue a teammate. Keep in mind that your fire rate will decrease rapidly if you are grabbed by zombies.
- Take advantage of explosives like the Pipebomb or Grenade. They can take out large numbers of zombies at once, which is useful if you get cornered or surrounded. However, bear in mind that their large blast radius can be a double-edged sword, as the explosion can easily kill a member of the party without proper consideration.
- Move around the perimeter of the map. Do not get cornered! Zombies will collect toward the center of the map and you may easily be able to leave the map once the timer runs out.
- Hide in a bathroom or kitchen. During some sieges in locations like houses, other rooms may be accessible. Hiding far enough from the door may prevent zombies outside the room from noticing you. Zombies can still fall from the ceiling or funnel through the door, but they are often fewer and easier to deal with. Then you can just lure zombies through your choke point to dispose of at your leisure. This strategy is less advisable in late-game sieges or on outdoor maps, however with enough firepower and party members you can kill large hordes as they bottleneck into your holdout area through the single doorway.
During the final day before entering Canada, two different sieges will occur:
- A 1.5-hour siege, which will take place inside a large house or cabin
- The Final Siege, which takes place in a large city block
You must survive both sieges in order to enter Canada's Border.