Fantasy Life has 3 different save games or profiles. However, Fantasy Life operates in a funny way. The game saves on the SD card, so if you took out the physical game cartridge and put it in another 3DS, there will not be any save data on it. This is a bad move on the developer’s part because if something were to happen to your sd card or 3ds for any reason, you would have to start the game all over.
I found this out the hard way. I switched out my Fantasy Life game to play on my brother’s 3Ds because my 3Ds had run out of batteries during the Fantasy Life event.
From my understanding, the SD card is linked to your own personal DS. So me simply switching my SD card into my brother’s 3Ds won’t cut it. In short–your save file is non-transferable. If something were to happen to my DS, then maybe I’ll lose everything. I stumbled upon this article which bought to mind that this does function very similar to an eshop game, except it’s not saved to any particular account thats secured online.
On the other viewpoint, at least you can swap the game among family members, significant others, or friends because you can easily share this game without worrying about your own save file being erased or tampered with in any way.