How to Mod Terraria: Install tModLoader and Mods (2026)

To mod Terraria on PC you install tModLoader, a free, separate app on Steam that loads mods from the Steam Workshop. There is no mod menu in Terraria itself, and nothing to patch. This guide covers how to mod Terraria from start to finish: installing tModLoader, getting mods, playing a modded world with friends, and running the same mods on a server so the world stays up when you log off.

One thing matters more than anything else in 2026. tModLoader is still built on Terraria 1.4.4.9, while vanilla Terraria is on 1.4.5. The tModLoader team is porting to 1.4.5 but has not set a date. Everything below works. What catches people out is that vanilla and modded Terraria are currently two different versions of the game, so your newest vanilla characters and worlds cannot come with you yet.

How Terraria modding works

• tModLoader is its own game in your library. Its Steam page lists it as a free mod for Terraria. To install it you must own Terraria on Steam, and it sits next to vanilla rather than replacing it. You can play both.
• Mods are .tmod files. You get them from the Steam Workshop, either inside tModLoader or on the tModLoader Workshop page.
• Modded and vanilla do not mix online. A tModLoader client cannot join a vanilla server, and a vanilla client cannot join a tModLoader server. Everyone in a modded game runs tModLoader with the same mods.
• Modded saves are separate. tModLoader has its own Players and Worlds folders, so modding never touches your vanilla saves.

Step 1: Install tModLoader on your PC

1. Search Steam for tModLoader and install it. It is free. If you play Terraria through Family Share, tModLoader will not launch through Steam. The tModLoader wiki has a manual-install workaround, but it only supports joining by IP, not Steam invites.

2. Launch it once. Its saves live in their own folder:

   OS	tModLoader save folder
   Windows	%UserProfile%\Documents\My Games\Terraria\tModLoader
   Linux	~/.local/share/Terraria/tModLoader
   macOS	~/Library/Application Support/Terraria/tModLoader

3. On first launch, tModLoader offers to copy your vanilla characters and worlds. It copies them and leaves the originals alone. Anything you made on Terraria 1.4.5 will show as (LaterVersion) and will not load. That is expected, and the next section explains why.

Budget the RAM

tModLoader lists 6 GB of RAM as its minimum, and its wiki says that minimum goes up with every mod you enable. Large content mods are the main culprits. In Settings → tModLoader Settings, turn on Show Mod Memory Estimates to see which mods cost the most.

Why your newest vanilla saves show "(LaterVersion)"

tModLoader's default branch is "currently based on Terraria 1.4.4.9 content". Terraria 1.4.5 ("Bigger and Boulder") came out on 27 January 2026, and the dedicated server is now at 1.4.5.8. A character or world saved by a newer Terraria cannot be opened by an older one, and tModLoader's own FAQ says to "wait for tModLoader to update to use that player or world".

Where things stand, as of 28 September 2026:

• The latest stable tModLoader release is v2026.07.3.0, published 1 September 2026. The next monthly 1.4.4 release is due on 1 October.
• On 1 September 2026 the tModLoader team wrote that they were "still not ready to set a release date" for 1.4.5 becoming the default. A 1.4.5-dev beta branch exists for testing.
• The team has said the 1.4.4 version and its mods "will continue to exist" as a legacy branch once 1.4.5 ships.

In practice, start a fresh character and world in tModLoader, or bring over saves from before 1.4.5. Do not try to force a 1.4.5 world into it.

Step 2: Download and enable mods

1. From tModLoader's main menu, open Workshop → Download Mods. You can also subscribe from the tModLoader Workshop at steamcommunity.com/app/1281930/workshop/.
2. Search for a mod and download it. Check the mod's page for anything else it needs.
3. Go back to Workshop → Manage Mods, enable what you downloaded, and click Reload Mods.

Large content mods often come in parts. Calamity, for example, says on its Workshop page that it "REQUIRES Calamity's soundtrack", which is a separate Calamity Mod Music item. Read each mod's description before you build a list.

If a mod crashes tModLoader on launch

Hold Shift while tModLoader loads. That skips mod loading until you reach the main menu. Then disable the broken mod in Manage Mods. Unsubscribe from Workshop mods on Steam; do not delete files from steamapps\workshop\content\1281930 by hand.

Where the big content mods stand (checked 28 September 2026)

Calamity's status is unsettled, so pin your versions

Calamity is still on the Workshop and still installs. Its last update, 2.2.4 (published to the Workshop on 10 August 2026 UTC), was a crash fix that the Calamity wiki says "was released as a hotfix by the tModLoader dev team to allow time to sort out Calamity's dev team plans". Press reports in August said the mod is shutting down. Calamity's own team had not confirmed a roadmap at the time of writing. If you run it on a server, pin the Server Version rather than tracking latest, so a tModLoader update cannot break a mod that may not get another patch (see Maintaining your Terraria server).

Step 3: Play modded Terraria with friends

There are two ways to play modded Terraria with friends, and they need the same things: every player on tModLoader, the same tModLoader version, and the same mods.

• Host & Play from your own tModLoader. Quick, but the world runs on your PC and shuts down when you leave.
• A dedicated tModLoader server. The world stays up without you, and nobody's framerate pays for hosting. This is what the rest of this guide sets up.

If a friend sees "You are not using the same version as this server", they are either on a different tModLoader version or trying to join from vanilla Terraria. The fix is to match versions. Networking has nothing to do with it.

Switching your server to tModLoader

1. In the Startup tab, set Server Type to tmodloader.

Check the Startup tab has a Server Type field before you follow this

Server Type exists on our multi-type Terraria image, which runs vanilla, TShock or tModLoader from one
setting. Our standard Terraria plan currently ships the plain vanilla image, and that image has no Server
Type field at all — its Startup tab carries the version, world name, size, difficulty, MOTD, password and
anticheat, and nothing else. If yours looks like that, the steps below will not work as written and the
options will not appear. Open a ticket before going further rather than hunting for a field that is not there.

2. Set World Name to a new name (see the warning below).

3. Go to Settings and click Reinstall Server. This replaces the server files with the latest tModLoader release from GitHub. Your existing worlds and data stay in place.

4. Start the server. A fresh tModLoader world generates on first boot.

Give the modded world its own name

tModLoader writes its mod data to a .twld file next to the world's .wld. Two things go wrong if vanilla and tModLoader share a World Name. A world last saved by vanilla 1.4.5 will not open in tModLoader (the LaterVersion problem above). And a modded world loaded in vanilla loses its modded tiles and items. Give each server type its own World Name, and switch the World Name whenever you switch types. Your other worlds stay in worlds/ until you switch back.

The version number is supposed to look old

tModLoader intentionally runs on an older Terraria version than vanilla and TShock (the console banner shows both, for example Terraria Server v1.4.4.9 - tModLoader v2026.5.3.0). This is not your server being outdated: players join with the tModLoader client, which runs on that same base version automatically, so everything matches on their end.

Putting your mods on the server

The server does not download Workshop mods itself on our image. You upload the .tmod files. The easiest way to get the exact files your client is running is a mod pack:

1. In tModLoader, enable exactly the mods you want on the server, then click Reload Mods.

2. Go to Workshop → Mod Packs → Save Enabled as New Mod Pack and give it a name.

3. Click Open Mod Pack Folder and open the folder with your pack's name, then its Mods folder. tModLoader has copied every loaded mod's .tmod file here, along with enabled.json, install.txt and tmlversion.txt.

4. Stop the server. Using the File Manager or SFTP, upload the .tmod files and enabled.json to tmodloader/Mods/ on the server.

5. Check tmodloader/Mods/enabled.json. It is a plain JSON array of internal mod names:

   [
     "ThoriumMod",
     "CalamityMod"
   ]
   

6. Open tmlversion.txt from the pack. It holds the tModLoader version your client ran. If it differs from the version in the server's console banner, set Server Version to that release tag (with a leading v, for example v2026.07.3.0) and reinstall so the two match.

7. Start the server.

Most content mods have to be on both sides: on the server, and in every player's tModLoader. Share the pack's mod list with your group, or send them the Workshop links. Mismatched mod lists are the most common reason people cannot join.

Troubleshooting a modded server

• "You are not using the same version as this server": the client's tModLoader version, or vanilla vs modded, does not match. Compare the console banner with the version on the client's main menu.
• Stuck on "Connecting…": the tModLoader wiki says this is usually a mod that fails on the server. Start the server with no mods enabled, then add them back a few at a time until it breaks. Check the console for red errors naming a mod.
• A mod does not load: an enabled.json syntax error, often a trailing comma, stops the whole list. Also check that the .tmod file name matches the name in the list.
• The world is suddenly empty after switching type: you are pointed at a different world file. See the World Name warning above.

What to Read Next

• Maintaining your Terraria server and back up before any mod change

• TShock Setup if you want moderation tools alongside mods

• Terraria Server Commands for the console commands that still apply under TModLoader

• Getting started with your Terraria server for the Startup variables and uploading worlds

• Is Terraria crossplay? — tModLoader locks mobile players out; worth knowing before you commit a world to it

---

Made with 💜 by GameServerKings