Where does “Miyako” come from?

Miyako (English) comes from Japanese 宮古島, from Japanese 島, from Middle Chinese 島.

Ancestry of “Miyako”, step by step

Step	Language	Word	Meaning
1	Japanese	宮古島	—
2	Japanese	島	an island; one's domain, territory, turf
3	Middle Chinese	島	—

Miyako — Etymology, Origin & Word History | Etymology Explorer