Things You'll Need
Instructions
Plug your USB drive into one of the four open USB ports on your PlayStation 3 console.
Turn on your PlayStation 3 and log in to your account. Scroll down to the Saved Data Utility option.
Select the game save you want to back up and press the triangle on your PlayStation 3 controller, then click "Copy."
Select your USB drive to back your saved data to your thumb drive and wait for it to copy over. PS3 saves are not large files so they should only take a few seconds to copy.