Translation guide
Indonesia is a country name. In Japanese, it is almost always expressed as インドネシア. There is also a formal kanji name 印度尼西亜, but this is rare and literary.
I plan to travel to Indonesia next year.
Ateji (kanji used phonetically) for Indonesia. Very rare, mainly found in historical or formal documents. The reading is the same as the katakana form.
Republic of Indonesia (formal name)