Maverick searched all over Destiny Islands for Selphie’s Life Preserver, to no avail. He is sharing his findings here so you don’t have to do the same.
How To Find Selphie’s Life Preserver in Kingdom Hearts Re:Coded
Selphie’s Life Preserver is in a backdoor at Destiny Islands. If you came here, though, you likely already searched all over the place with no luck. That is likely because you have not upgraded your Scan ability yet, which is required to find the relevant backdoor.
How To Upgrade Your Scan Level in Kingdom Hearts Re:Coded
You start off the game with a basic level of the Scan ability. To upgrade it, you need to path to the relevant blocks in the Stat Matrix.
The issue with Selphie’s Life Preserver is that most people will discover the quest before they notice how to upgrade Scan. It is technically possible to upgrade it at the end of Alice in Wonderland before starting the Olympus Coliseum story. It is easy to miss, though. You can see the block you need to path to in the image above. It is at the bottom right of the Stat Matrix at the time it unlocks.
Other quests in Kingdom Hearts Re:Coded follow the same system. You usually first need to unlock the next level of Scan before you can complete the next quest in a world. It’s not always at a 1:1 ratio, however. For example, it is possible to find Alice’s teacup before upgrading your Scan at all.
The main thing to remember is that if you collected all rewards from a backdoor and you are not getting alerts for new ones, it’s no use to keep looking. You’ll need to wait for the next Scan Block to unlock, path to it, and then return to finish the quest.