Board Thread:Kancolle for Android/@comment-30538704-20190910205446/@comment-26461371-20191009065816

Yes, you only need to download the game and log in with the same account to get your data back. It's the same reason why you don't get your naval base reset if you log in on a different computer or even a different browser in the same computer.

It will have to re-download some game assests that would've been cached in your old device (like ship images, in-game screens, furniture, BGMs, etc...) but this is general data that isn't related with your personal data (which is saved with your DMM account).