How to Install Call of Duty: Black Ops III and Join a Server

The reason to install Black Ops III on a PC in 2026 is almost never the game Treyarch shipped. It is a Zombies map somebody built in their spare time — a haunted hotel, a recreation of a level from a different game entirely, a sprawling puzzle box that takes four people six hours to finish and has its own wiki.

That is an unusual thing to be true of a mainstream Call of Duty, and it happened for one specific reason. The PC version got official mod tools and Steam Workshop support, and a decade later that decision is the whole story of why anybody is still here.

This guide is about getting the game running, understanding what "joining a server" means for a title built around matchmaking rather than server browsers, and getting into custom content without breaking your install. Listings collect on the Black Ops III hub.

Set expectations about the connect model first

Most of the games covered on this site work the same way underneath. There is a machine somewhere with an address, you type that address into a console, and you are in. Counter-Strike works like that. So does everything built on the same engines.

Black Ops III does not.

This is a matchmaking-era Call of Duty. There is no developer console you type connect into, no in-game browser listing hundreds of public machines by IP, and no expectation that a stranger will run a persistent server for you to walk into. The multiplayer is a queue. The custom content is a lobby somebody hosts and invites people to.

That is worth saying plainly rather than pretending otherwise, because a guide that promises a server browser this game does not have is a guide that wastes your evening. What follows is how it actually works.

What you need

A Steam account, the game, and a substantial amount of disk space. Black Ops III is a large install by any standard, and custom Zombies maps are large on top of that — individual community maps run to gigabytes on their own, and a subscription list of a dozen of them is a real storage commitment.

If Steam is new to you, the Steam install guide covers making an account and securing it properly.

The game is paid and it goes on sale regularly. What a given store listing includes has varied a great deal over the years — base game, various editions, season passes, standalone bundles — so read what you are buying rather than assuming the cheapest entry contains everything you have seen people playing.

Hardware sits in an awkward place. A 2015 game is not demanding by current standards, but this one was built for a generation of consoles and it is heavier than its age suggests. Custom Zombies maps make it worse, because community mapmakers are not bound by the memory budgets that constrained the official ones. A map that four people are running smoothly on modern machines might be unplayable on an older laptop.

The three games in the box

Multiplayer is the specialist-and-movement era of Call of Duty. Wall-running, sustained thrust jumps, sliding into cover — chained together, they make for a much faster and more vertical game than the series' earlier entries. Playable specialists each bring a signature weapon or ability that charges up over a round.

It is also the part of the game with the worst reputation on PC, for a reason that is not about design. The matchmaking population has a long-standing problem with cheating, and it has had that problem for years. Anybody who tells you otherwise has not queued recently. That is a large part of why the interesting community activity moved to private lobbies and custom content.

Zombies is the round-based co-operative mode: four players, an enclosed map, waves of enemies that get faster and tougher until they kill you. Between waves you spend points on opening doors, buying weapons off walls, drinking from perk machines and upgrading guns at the machine that exists on nearly every map in the series. Layered on top is a quest — a chain of obscure steps in a specific order, undocumented in the game, that a community works out collectively in the first week and then everybody follows.

The campaign is a co-operative campaign, which is unusual for the series and worth knowing if you have three friends and no interest in competitive play.

The Zombies routine, for people who have never played it

Custom maps assume you know how Zombies works. Nothing in them teaches it. Here is the shape, because it is the same on every map in the series and it is entirely learnable in one evening.

Points are the currency and you earn them by damaging and killing. You spend them on opening the map up — doors and barriers that cost a fixed amount and stay open for the rest of the game — and on weapons, either bought off a wall at a fixed price or pulled at random from the box that relocates itself after it has been used enough times.

Early rounds are a routine rather than a fight. The zombies are slow, there are few of them, and the correct behaviour is to kill them inefficiently on purpose so that each one pays out more. Experienced players use a knife for the first couple of rounds for exactly this reason. Rushing the early game with a good weapon leaves you broke at round eight with half the map still locked.

Then there is the technique that everything else rests on: gathering the horde into one group and running it in a loop around an open space. Zombies path towards you and clump behind you, so a player who keeps moving in a wide circle can hold thirty of them in a train and pick off the ones at the front. Standing still in a corridor is how rounds end. This is the single skill that separates somebody who reaches round ten from somebody who reaches round thirty.

Two more fixed points. Most maps require you to find and switch on the power before the useful machines work. And the upgrade machine — the one that takes a weapon and makes it viable past the mid rounds — is generally hidden behind a step or two of the map's own puzzle.

Perks are bought from machines, they cost a lot, and you lose them when you go down. That is the real penalty for dying, more than the revive itself.

Custom maps, which is the actual reason

Treyarch shipped mod tools for the PC version and wired them into the Steam Workshop. The consequence is a decade of community Zombies maps, and the good ones are far more ambitious than anything the studio shipped.

The mechanics of using them are simple. Subscribe on the Workshop, let Steam download the map, launch the game, and find the mods section in the menus. Custom maps appear there rather than in the standard Zombies map list.

Two pieces of advice that will save you an evening.

Do not subscribe to fifty things at once. Every subscribed item is content the game has to account for at startup, and a bloated list is the most common cause of long load times and crashes. Subscribe to what you intend to play this week.

Everybody in the lobby needs the same map. This is the single most common failure. If three of you have subscribed and one has not, or one has an older version because Steam has not finished updating it, the fourth person cannot join. Confirm everyone has the same content downloaded before you start.

Getting four people into the same game

The practical routes, in the order most people use them.

Steam friends. The host starts a private or custom lobby and invites people through Steam or through the in-game friends list. For a group of four this is the whole process and you can stop reading here.

A community's Discord. This is where custom Zombies actually lives. Maps have their own communities, big maps have their own servers full of people looking for a fourth, and the round-based quest content is close to impossible to complete with strangers who have not read anything. Finding the group is the real task, and it is a social one rather than a technical one. The communities directory is one starting point, and how Discord changed the way gaming communities organise covers why almost all of this now happens there rather than on forums.

A hosted lobby someone advertises. Some groups run scheduled sessions on custom content and post an invite. What that looks like technically varies by group. If you are given an address rather than an invite, the group will also tell you what to do with it, because the mechanism is not something the game surfaces in its own menus.

Listings for the game collect on the hub, and if you are trying to work out which advertised session is worth turning up to, how to find the best game servers is about that judgement more generally.

Problems

A friend cannot join your custom map lobby. Content mismatch. Check that everybody has the identical Workshop item, fully downloaded, at the same version.

The game takes minutes to launch. Too many Workshop subscriptions. Unsubscribe from what you are not playing.

A custom map crashes on load. Some community maps are more demanding than the base game and some were built against older versions of the tools. Check the map's own Workshop page, where the author and the comments will tell you whether it is the map or you.

Matchmaking puts you in games with obvious cheaters. This is the known state of the PC matchmaking population rather than something on your end. Private lobbies with people you know are the working answer.

Poor performance despite the game's age. Turn down the settings tied to lighting and shadows first. This engine generation spends more on those than on anything you will notice missing.

Where to go next

If Zombies is what brought you, the mode started in Call of Duty: World at War, which is where the first map and the original four characters came from, and it continued through the first Black Ops. Both have communities that never left.

If what you want is the older, faster, server-browser-shaped Call of Duty rather than the matchmaking era, that is a genuinely different set of games. Call of Duty 2 and Call of Duty 4 both come from the period when the series shipped with dedicated servers and a browser full of community machines running their own rules, and both still have people on them. The original Call of Duty is where that started.

That is the honest recommendation for anybody who found this article looking for a server list. Black Ops III is a good game with a remarkable custom-content scene attached to it. It is not a community-server game, and the earlier entries in its own series are.

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JoinGG is a live directory of community game servers. Every listing is queried directly every fifteen minutes, so the player count you see was measured rather than reported by its owner, and each one carries a copyable connect address. Call of Duty: Black Ops III servers are listed here, and every game on the site has its own hub. Player counts across every game are on the statistics page.