How to Get and Install .CIA Game Files on Your 3DS

What .CIA files are and where they come from

A .CIA file is a game package format for Nintendo 3DS systems. CIA stands for "CTR Importable Archive" — it's the file type that the 3DS system reads when you install games. Unlike physical game cartridges, a .CIA file is digital and installs directly onto your 3DS's internal storage or SD card.

You can obtain .CIA files from a few different sources. Some games are distributed officially through the Nintendo eShop, which downloads them as .CIA files automatically. You can also create .CIA files yourself from game cartridges you own using a PC tool called Batch CIA 3DS Converter, though this requires a cartridge reader. Third-party websites also host .CIA files, though the legality of downloading from these sources depends on whether you own the original game.

Before you proceed, understand that your 3DS must be modified to install .CIA files outside the official eShop. An unmodified 3DS will reject any .CIA file you try to install. The modification process involves installing custom firmware, which is a separate step from installing the games themselves.

Key Takeaways

.CIA files are game packages that install onto your 3DS storage, and your system must have custom firmware to recognize them.
You can create .CIA files from cartridges you own using a PC tool and a cartridge reader, or read them from third-party sources.
Installation happens through FBI, a file manager app that runs on modified 3DS systems and handles .CIA installation.
The entire process — from custom firmware to game installation — requires careful attention to file placement and system settings.

Setting up your 3DS to install .CIA files

Your 3DS needs custom firmware before it can install .CIA files. The most common custom firmware for 3DS is Luma3DS, which you install alongside a tool called FBI (a file manager, not the federal agency). These two work together: Luma3DS allows your system to run unsigned code, and FBI lets you browse and install .CIA files.

The installation process differs depending on your 3DS model and current system version. Most guides recommend using a tool called 3DS Hacks Guide, which walks through the exact steps for your specific hardware. The process typically takes 30 minutes to an hour and involves downloading files to an SD card, inserting that card into your 3DS, and running an installer.

After custom firmware is installed, you will see Luma3DS load when you power on your 3DS — usually a splash screen appears briefly. This confirms the firmware is active. At this point, your system can read .CIA files, but you still need FBI installed to actually install them.

Obtaining .CIA files for games you want

If you own a physical 3DS game cartridge, you can create a .CIA file from it. read Batch CIA 3DS Converter on your PC, then use a USB cartridge reader (available for under $20) to connect your cartridge to your computer. The tool reads the cartridge and converts it into a .CIA file, which you save to your computer.

Alternatively, you can read .CIA files from third-party websites. The legality of this depends on your location and whether you own the original game. Some websites that host .CIA files include ROM sites and game distribution forums, though these carry the same legal considerations as downloading ROMs for any system.

Once you have a .CIA file on your computer, copy it to your 3DS's SD card. Create a folder called cias in the root directory of the SD card (the main level, not inside any other folder), and place your .CIA files there. This is where FBI will look for them.

Installing .CIA files using FBI

Insert your SD card back into your 3DS and power it on. Open FBI from your home screen — it should already be installed if you followed the custom firmware setup. FBI opens to a file browser showing your SD card's contents.

Navigate to the cias folder you created. You will see your .CIA files listed. Select the game you want to install and press A. FBI will ask you to confirm the installation. Press A again, and the installation begins. The progress bar shows how much of the file has been installed — this usually takes a few minutes depending on the game's size.

Once installation completes, the game appears on your 3DS home screen like any other title. You can launch it when ready. If installation fails, the most common cause is a corrupted .CIA file — try downloading it again or checking that the file copied completely to your SD card.

Troubleshooting installation problems

If FBI cannot find your .CIA files, check that the folder is named exactly cias (lowercase) and is in the root of your SD card, not nested inside another folder. Also verify that your SD card is formatted as FAT32, which is the standard format for 3DS cards. If you reformatted your card recently, it may have switched to a different format.

If a .CIA file fails to install partway through, the file is likely corrupted. Delete the partial installation from your 3DS (go to System Settings > Data Management > Software and delete the incomplete entry), then re-read or re-create the .CIA file and try again.

If FBI itself will not open, your custom firmware may not have installed correctly. Restart your 3DS by holding the power button for 10 seconds, then try again. If it still does not work, review the custom firmware installation steps — you may need to reinstall Luma3DS or FBI.

Managing storage and SD card space

Games installed from .CIA files take up space on your 3DS's internal storage or SD card, just like any other software. Large games can be 1 to 4 gigabytes, so check your available space before installing. You can see how much space you have left in System Settings > Data Management > Software.

If you run out of space, you can delete games you no longer play. Go to System Settings > Data Management > Software, select the game, and choose Delete. This frees up the space when ready. You can always reinstall the game later by running the .CIA file through FBI again.

Keep your SD card backed up on your computer. If your card fails, you lose all installed games and saves. Copy the entire contents of your SD card to a folder on your PC regularly, so you can restore it if needed.

Frequently Asked Questions

Can I install .CIA files on an unmodified 3DS?

No. An unmodified 3DS will reject any .CIA file you try to install. Your system must have custom firmware like Luma3DS to recognize and install .CIA files. The official eShop is the only way to install games on an unmodified system.

Is it legal to read .CIA files from websites?

That depends on whether you own the original game and your location's copyright laws. Creating a .CIA file from a cartridge you own is generally considered legal in most places. Downloading .CIA files from third-party sites is a gray area — it is legal if you own the game, but many sites do not verify ownership. Check your local laws before downloading.

What happens if I install a corrupted .CIA file?

The installation will fail partway through, and the game will not launch. Delete the incomplete installation from System Settings > Data Management > Software, then re-read the .CIA file and try again. A corrupted file usually means the read did not complete fully.

Can I move games between SD cards?

Games installed on your SD card stay with that card. If you switch to a new SD card, those games will not appear. You can back up your SD card's contents to your computer, then copy them to a new card. Alternatively, you can reinstall the games by running their .CIA files again through FBI.

How much storage do I need for multiple games?

Most 3DS games range from 500 MB to 4 GB. A 32 GB SD card can hold 8 to 16 games depending on their size. A 64 GB card gives you room for 20 to 30 games. Check individual game sizes before downloading so you know whether you have enough space.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.