Multiple Release

I know it won't release in North America, but has it released multiple times in Japan? Like, was it a one time thing or a reoccurring event? Also, how do you actually get there? If you need an item from the island to get there, then shouldn't it be impossible to access it even during the event?

User:Luin plays on JP and I asked him and he says it's always open. He doesn't quite remember how to get there initially but he thinks it was with a keyword.

Yep, you get a quest and a keyword from it. Use keyword on Shenan in Port Ceann and you can get there. You can buy a fixed Goddess Wing from an NPC there so you can make the return trip anytime afterwards.