How to Use a USB Flash Drive With Your Phone (USB OTG)

Published 2026-10-16 · Marion Phone Repair

You have files on a USB flash drive that you need on your phone, or files on your phone that you want to move to a flash drive — and you do not have a computer nearby. Most Android phones and some iPads can connect directly to a USB flash drive and read or write files to it, just like a computer would. The feature is called USB OTG (On-The-Go), and all you need is a small adapter cable.

What USB OTG is

USB OTG is a standard that allows a phone or tablet to act as a USB host — the same role a computer plays when you plug in a flash drive, keyboard, mouse, or other USB device. Without OTG, your phone can only act as a peripheral (when you plug it into a computer, the computer is the host and the phone is the device). With OTG, the phone becomes the host and can read flash drives, external hard drives, USB keyboards, game controllers, and other USB accessories.

What you need

An OTG adapter or cable

The adapter connects your phone's port to a standard USB-A port (the full-size rectangular port on flash drives):

If your phone has USB-C (most phones from 2018 onward): You need a USB-C to USB-A adapter (also called a USB-C OTG adapter). These are small dongles, roughly the size of a thumb, that cost a few dollars
If your phone has Micro-USB (older phones): You need a Micro-USB to USB-A OTG adapter. Same concept, different connector
Alternatively: Buy a dual flash drive that has both USB-A and USB-C connectors built in. These plug directly into a USB-C phone without any adapter. SanDisk, Samsung, and others make these — they are convenient if you regularly transfer files between phone and computer

A phone that supports OTG

Most Android phones from the last 5 to 6 years support USB OTG. To check if yours does:

The simplest test is to plug in a flash drive (with an adapter) and see if the phone recognizes it. If a notification appears saying USB drive connected or a file browser opens, your phone supports OTG
You can also search for your phone model plus USB OTG in a search engine to confirm support
Some very budget phones omit OTG support to cut costs, but it is standard on mid-range and flagship devices

iPhone and iPad compatibility

iPhones with a Lightning port (iPhone 14 and earlier) can read USB flash drives using a Lightning to USB-A adapter (Apple's Lightning to USB Camera Adapter or a third-party equivalent). The iPhone 15 and later models with USB-C can use a standard USB-C to USB-A adapter. iPads with USB-C have native support. The Files app on iOS handles the file browsing. However, iOS is more restrictive than Android about which file types you can open and where you can save files — you can view photos, videos, and documents, but you cannot install apps or access system files from a flash drive.

How to connect and use a flash drive on Android

Plug the OTG adapter into your phone's USB-C (or Micro-USB) port
Plug the flash drive into the adapter's USB-A port
Within a few seconds, you should see a notification that a USB drive has been detected. Tap the notification to open the file browser
If no notification appears, open your phone's file manager app (Files by Google, Samsung My Files, or whatever file manager your phone came with) and look for the USB drive in the storage locations list — it usually appears as USB Storage, USB Drive, or the brand name of the flash drive
Browse, copy, move, and delete files just as you would on a computer. You can copy photos from your phone's internal storage to the flash drive, or copy documents from the flash drive to your phone

File format compatibility

Android supports the most common file systems used on flash drives:

FAT32: Supported by essentially every device. Maximum file size is 4 GB, which is a limitation if you are transferring large video files
exFAT: Supported by most modern Android phones. No practical file size limit. This is the best format for flash drives used between phones and computers
NTFS: Some Android phones can read NTFS drives but not write to them. NTFS is the default Windows file system — if your flash drive is NTFS and your phone cannot write to it, reformat it as exFAT on a computer
ext4: Linux file system. Rarely used on flash drives but supported by some Android phones since Android is Linux-based

What you can do with USB OTG

Transfer photos and videos

The most common use. Moving photos from your phone to a flash drive frees up phone storage and gives you a physical backup. Navigate to your DCIM/Camera folder in the file manager, select the photos and videos you want to move, and copy or move them to the USB drive. This is especially useful when your phone storage is full and you do not have cloud storage or a computer available.

Move files between devices

A flash drive is the simplest way to move files between two phones, or between a phone and a computer, without internet access. Copy files to the flash drive from one device, unplug, and plug into the other. No Wi-Fi, no Bluetooth pairing, no cloud account needed.

Play media directly from the flash drive

You can play music and video files directly from the flash drive without copying them to your phone. Open the file from the file manager and your phone's default media player handles playback. This is useful for watching movies on a long trip without using your phone's storage — load a flash drive with movies on your computer, plug it into your phone with an OTG adapter, and watch directly.

Connect other USB devices

USB OTG is not limited to flash drives. You can also connect:

USB keyboards and mice: Useful for typing long documents on a phone or for accessibility purposes. Standard USB keyboards work immediately when plugged in — no pairing or setup needed
Game controllers: Wired Xbox and PlayStation controllers work with many Android games via OTG
USB DACs and audio interfaces: For higher-quality audio output than the phone's built-in DAC provides
Card readers: Connect an SD card reader to import photos from a camera's SD card directly to your phone without a computer
External hard drives: Larger external drives may require external power (a powered USB hub connected via OTG) because the phone's USB port may not supply enough power for a spinning hard drive. SSDs and bus-powered drives usually work fine

Troubleshooting

Phone does not recognize the drive

Try a different adapter: Cheap OTG adapters sometimes fail. Test with a known-good adapter
Try a different flash drive: Some very old or very large drives may not be compatible
Check the file system: If the drive is formatted as NTFS and your phone does not support it, connect the drive to a computer and reformat as exFAT (this erases all data on the drive — copy files off first)
Restart the phone: If OTG was working previously and stopped, a restart often resolves USB detection issues
Check OTG settings: Some phones (particularly Samsung and Xiaomi) have a USB OTG toggle in Settings that must be enabled. Search for OTG in your Settings app

Drive connects but shows empty

If the drive is recognized but appears empty when you know it has files, the files may be in a format or folder structure the file manager does not display by default. Try a third-party file manager like Solid Explorer or Total Commander, which show hidden files and support more file systems. If the drive is encrypted (BitLocker or similar), Android cannot decrypt it — you need a computer to access the files.

Files transfer slowly

Transfer speed depends on the slowest link in the chain — the flash drive's write speed, the phone's USB controller speed, and the adapter quality. USB 2.0 flash drives transfer at roughly 10 to 30 MB/s. A USB 3.0 flash drive through a USB 3.0-capable phone and adapter can reach 100 to 300 MB/s. If transfers are very slow (under 5 MB/s), the adapter may be USB 2.0 even if the drive and phone support USB 3.0.

USB and file transfer help in Marion

If you need help transferring files from your phone, recovering files from a flash drive that is not being recognized, or setting up a reliable backup system using external storage, Marion Phone Repair can help with file transfers, storage troubleshooting, and making sure your important data is properly backed up.