How to find opponents to PVP against in FOB

This is notably easier to do compared to an infiltrator. There are two main ways of attracting players to your FOB, enabling security challenge and having a nuclear weapon. Each have their perks which will be explained below.

By entering the security challenge tab of the FOB menu you can enable security challenge for your FOBs. As long as it is enabled, your FOB can appear in the security challenge tab for other players to find. However, it will automatically be disabled if the number of security guards available falls under the amount set for the FOB (but if you have 0 guards set security challenge will never be turned off automatically). Security challenge has the following quirks:

• When an infiltrator invades your FOB you will always receive an alert to defend no matter what.
  
• No retalitory wormhole will be created (except if the infiltrator disconnects or aborts).
  
• A blockade will not be raised after someone infiltrates your FOB, regardless of whether they reached the core or not.

After you enable it after waiting long enough typically you will get the alert for someone infiltrating your FOB. Do bear in mind that security challenge will not be turned off even if you close the game, so I would recommend turning it off if you do not plan to be in the game and/or defend as otherwise you may incur a lot of losses whilst you are offline. This is harder to do compared to enabling security challenge as it requires you to obtain a nuclear weapon first, either by making it yourself or stealing it from another player. Having a nuclear weapon will allow other players to find you in the nuclear weapons tab of the FOB missions menu regardless of rank. Having a nuclear weapons has the following quirks, some different to security challenge:

• When an infiltrator invades your FOB you will always receive an alert to defend no matter what.
  
• You will receive a wormhole to the infiltrator as long as they were spotted at least once.
  
• A blockade will be raised after the infiltrator is either neutralised, disconnects, or reaches the core. The duration of the blockade increases in accordance to how many nuclear weapons you have, although this caps at a certain point (I believe the maximum blockade duration is around a week).

Do bear in mind that by attracting players to your FOB, you are very likely to incur damages including injured/killed guards, stolen staff, and resource/GMP loss. Additionally, cheaters may infiltrate your FOB!

There are three main ways of finding defenders to fight against (outside of organising matches directly with an individual), those being retalitory wormholes, finding FOBs with a nuclear weapon, or security challenge. To gain a better idea of whether a defender may deploy or not, you can open up the Steam profile of the player to see if they are in game. If their game activity is private but you can see their recently played games and MGSV was last played on the current day, chances are they are in game.

As mentioned before, security challenge can be used to find players to defend against, so conversely it can also be used to find defenders to fight against. However, not all FOBs found in the security challenge tab will result in a defender deploying. Security challenge FOBs can be loosely categorised into three categories - empty FOBs, charity FOBs, and players looking for PVP. The first two types are very unlikely to result in a defender deploying, and as such if you are looking for PVP matches these FOBs should be avoided. There are two main signs that can be used to determine whether an FOB is an empty one or not.

• No security guards are set (consequently the security level will typically be very low, around 1).
  
• The FOB has been in the security challenge tab for multiple days.

You will find that you will be seeing the same few empty FOBs on security challenge each day so you can keep a mental note of which ones are unlikely to result in a PVP match. Charity FOBs are those that are deliberately set up to provide other players with an easy way of gaining either resources or high rank staff. As such, these will not result in a defender showing up. There are two FOBs under this category that are most commonly seen in the security challenge tab:

• oumeded2012 - this FOB is the best for gaining resources as the security level has been artificially raised to level 99 meaning that it is fairly easy to successfully core and will net you a lot of resources for doing so. However, bear in mind that the S++ staff obtained from this FOB will revert to being A++ after being captured.
  
• 48216 - this FOB is great for obtaining S++ staff. The security has been set to be easily clearable with low level gear and you can gain a lot of S++ staff by fultoning the guards and reaching the core.

With the two aforementioned FOB categories in mind, the main way of identifying security challenge FOBs for PVP are if you have not seen that particular FOB before and they do not fall into either being an empty or charity FOB. As you keep playing for long enough, you may find some familiar FOBs that open themselves up for PVP.
If you find an FOB with no deployment spots, do not infiltrate it! Attempting to do so will cause the game to become soft locked. As of writing this guide there is currently an FOB on security challenge set up like this. For an FOB to have a nuclear weapon, it requires a player to have taken action in either making or stealing the nuke meaning that they are far more likely to have a defender deploy. However, finding an FOB with a nuclear weapon can require a lot of patience. You will be needing to opening and closing the nuclear weapons tab of the FOB missions menu repeatedly until you can find an FOB with a nuclear weapon. If the menu shows up as empty that does not mean that there are no FOBs with nuclear weapons, it just means you have to keep opening and closing the menu in hopes of finding an FOB with one eventually. In contrast to security challenge, infiltrating an FOB with a nuclear weapon can result in a retalitory wormhole being opened to your FOB allowing for more opportunities for PVP. If you are spotted during an FOB infiltration (outside of security challenge) or disconnect as an infiltrator, a retalitory wormhole to your FOB will open up for the opposing player to use. Wormholes can be a good way of finding other players to PVP against as they will only appear with the FOBs of active players. On top of direct wormholes from your FOB, you can also access the wormholes of players you support. To support a player, go to the relationships menu in the iDroid. There you will be able to support either people you are friends with on Steam or random players one rank above or below you (this means players with the highest rank will only be able to find random players one rank below them). If you are not friends with active FOB players, you can try finding random FOBs to support in hopes of getting wormholes to other players. I would recommend supporting FOBs that have a lot of S++ staff as these are more likely to be infiltrated. Although an indirect wormhole will disappear after use, this can be circumvented by performing dispatching staff to weaken the FOB and then infiltrating the FOB via the dispatch tab. This way you can keep infiltrating the FOB until the wormhole dissipates.

When you support another player in FOBs it becomes possible to go to their FOB via a visit or training. Both of these will send an alert to the FOB owner as well as other players who support them, allowing them to deploy for PVP. This allows for an easier way of having matches with friends however they come with some caveats that must be kept in mind.

The main benefit of doing PVP under training is that no resources or losses will be received for either player, mitigating one of the greatest issues FOBs has.

However, under training you cannot send any dispatches which is the main reason as to why most PVP players do not conduct matches using this method. It is possible to have the defender lower the security grade beforehand, but one thing they cannot modify is the reinforcements. Not being able to reduce reinforcements via a dispatch will result in essentially infinite reinforcements - thus making PVP much more difficult.

There are two workarounds to this, however. One is getting insurance (and only having S+/S++ staff in the security team) or having no eligible guards (sometimes you can find empty FOBs like this). Either way, the intent is to make the guard rank become E as E rank guards cannot call for reinforcements.

In summary, defenders can use either nuclear weapons or security challenge to attract infiltrators to their FOB. Conversely, infiltrators can find FOBs with nuclear weapons, on security challenge, or via retalitory wormholes to find defenders to fight against. I hope this guide has been helpful for those who wish to get into the PVP FOB offers. If you have any corrections and/or additions you would like to suggest to the guide, please provide it in a comment. Thank you for reading.