There are a few ways to obtain Strawberry Crates. Firstly, they can be found around the island. The crates don't respawn, but ...

Every area has Fast Travel Mailboxes Hello Kitty Island Adventure players can use to get around the islands (and beyond) ...

In Hello Kitty Island Adventure, you can find the Gemstone Critter List inside the Reef Critter Room in the Nature Preserve.