Update coming to Instagram's Android app to allow multiple accounts
You can get a shot at the update by signing up for Instagram's official Play Store Beta testing program. Or, you can install the APK files from APK Mirror (check out the sourcelinks). Once you install version 7.12.0 of the picture-sharing app, you will go to settings and scroll to the bottom. A new option, Add Account, will be found right underneath Clear Search History.
Users will be able to switch between accounts from their profile page. When it comes time to sign-off, you can close both open accounts at the same time, or close one and keep the other one active.
There is no word on when the update will be offered to all Instagram users rockin' Android. One little note. Android users are getting first crack at the new capability.
source: APKMirror via AndroidPolice