Although mobile devices have more storage space than ever before it’s so easy to fill up, wouldn’t it be nice if you could just pop a flash drive right into your device and expand your storage on the fly? Read on as we show you how mount a flash drive on your Android device.

Why Do I Want To Do This?

Even if your Android device has a micro SD slot, and not all devices do unfortunately, it’s still inconvenient to remove the SD card to load it up with content or transfer files (especially if you have apps that rely on SD card storage). It’s also inconvenient to tether your device or wirelessly transfer the files, especially for files that you may not need to store inside the phone on the internal storage or SD storage.

If you want to bring a bunch of movies on a trip to watch on the plane or in your hotel, for example, you really don’t need to clutter up your internal storage options with bulky media files. Instead, it’s much easier to just throw files on a cheap and spacious flash drive and then mount the flash drive when you want to watch the movies, unload media you’ve created on the phone to free up space, or otherwise enjoy a multi-gigabyte storage boost.

Rare is the Android device that comes with a full size USB port, however, so you’ll need a little techno-wizardy to make it happen. Let’s look at what you need and how to check if your device supports the required equipment.

What Do I Need?

The magic that makes it possible to mount a regular USB flash drive on your Android device is a a USB specification known as USB On-The-Go (OTG). The specification was added to the USB standard way back in 2001 but don’t feel bad if you’ve never heard of it. Although the specification is over a decade old now it wasn’t until Android 3.1 Honeycomb (released in 2011) that Android natively supported OTG.

The most important element of the OTG specification is that it gives Android the ability to specify whether it is the master or the slave role when connected to a supported device. In other words even though the general role of your Android device is to be the slave (you attach it to your computer via a data sync cable and your computer acts as the host) the Android device can be the host thanks to OTG and storage devices can be mounted to it instead. That’s the most important element as far as our tutorial is concerned but If you’re curious about the OTG specification in a broader sense you can check out the USB On-The-Go Wikipedia entry here.

A Phone That Supports OTG

Unfortunately, just because the specification is well established and Android has supported it for years doesn’t mean that your device automatically supports it. In addition to the required Android kernel component and/or drivers, there needs to be actual support by the physical hardware in your phone. No physical support for host mode via OTG, no OTG goodness.

Testing to see if your phone supports OTG is really easy, however, so don’t be discouraged. In addition to looking up the specs for your phone via search engine query you can also download a helper application, like USB OTG Checker, to test your device before investing energy into the project.

Note: It is possible to have a device that can support OTG on the hardware-level but that does not have the proper kernel/drivers for software-side OTG support. In such cases it’s possible to root a device and install drivers, flash a new ROM with OTG support, or otherwise remedy the situation, but those courses of action are beyond the scope of this particular guide and we note them simply so readers inclined to engage in such advanced tinkering know it’s a possibility. We recommend searching the excellent XDA-Developers forums for your phone’s model/carrier and the term “OTG” to see what other users are doing.

An OTG Cable

If your device supports OTG then it’s just a simple matter of picking out an OTG cable. OTG cables are dirt cheap, by the way, so don’t worry about breaking the bank. Although you can get OTG cables with all sorts of bells and whistles on them (SD card reader slots, etc.) we wouldn’t bother with the extras as it’s just as easy to plug in the devices you’re already using on your regular computer into a plain old dirt-cheap OTG cable.

In fact, the only real decisions to be made when it comes to OTG cable shopping are: whether you want to wait a month on shipping from Hong Kong to get the cheapest one possible and whether or not you want an OTG with charging capabilities.

If you’re willing to wait on shipping, you can pick up a non-powered OTG cable for, we kid you not, $1.09 with free shipping. You’ll wait a few weeks for it to get sent parcel post from Hong Kong but it’ll cost you less than a truck stop cup of coffee. If you want a non-powered OTG cable right now, you can pick up this model for $4.99 with free Prime shipping.

If you plan on doing some serious media watching on your device using an OTG mounted flash drive, we’d recommend picking up an OTG cable with a power-passthrough so you can use a standard charging cable to pump juice to your device while you’re catching up on your favorite shows.

Again, if you’re in no rush you can pick up a powered OTG cable for $1.81. If you want it right now, you can pick up a similar model for $4.99 with free Prime shipping.

A Flash Drive

The final thing you need is a simple flash drive or other USB media (an external powered portable hard drive, an SD card in an SD card reader, etc. will all work). The only critical thing is that your flash media is formatted in FAT32. For the purposes of this tutorial we’re using the sturdy little Kingston Digital DataTraveler SE9 but any properly formatted and functioning drive will do.

Mounting the Drive

Just like with our How to Connect Your Android Phone to Your TV guide, the hardest part is checking your hardware and buying the right cable. Once you have the right hardware and the right cable, the experience is pure plug and play goodness.

Plug the OTG cable into your Android device (if you have a powered OTG cable, connect the power source at this time too). Plug the storage media into the OTG cable. You’ll see a notification in your notification bar that looks like a little USB symbol. If you pull the notification drawer down you’ll see a notice that there is now an attached USB storage option. You don’t have to do anything at this point as the drive is already mounted and available to Android.

If you do tap on the notification (or navigate to Settings ->Storage) you can take a closer look at the USB storage options.

When you’re done with the flash storage, this is the menu you want to visit in order to use the “Unmount USB storage” option to properly unmount and remove your media.

Otherwise, feel free to jump right into using the removable media. You can browse the file structure in the native Android file browser or your file browser of choice, you can copy files to and from the device, and you can watch any media stored on it.

Here is our flash drive as seen in the drive-selection menu in ES File Explorer, listed as “usbdisk.”

And here’s a screenshot of our file transfer test using the same file explorer.

File transfer is snappy as is media playback. Thanks to OTG we no longer need to crack open the case of our device to get at the micro SD card or play any advanced games balancing the storage load on our internal memory. For the dirt cheap price of an OTG cable and a big flash drive we can instantly expand our storage (and easily swap it out).