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.
Referring to the country Indonesia
The standard Japanese name for Indonesia, used in all contexts.
インドネシアは東南アジアの国です。
Indonesia is a country in Southeast Asia.
来年インドネシアに旅行する予定です。
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.
印度尼西亜共和国
Republic of Indonesia (formal name)