I think you can self-learn Japanese to a point. You can certainly become proficient enough to read written Japanese, as long as you have both the time and patie

I think you can self-learn Japanese to a point. You can certainly become proficient enough to read written Japanese, as long as you have both the time and patience to learn and review Kanji compounds (too many resources focus too much on individual Kanji, and not enough on the many compounds you'll actually see in text). You can also become proficient in understanding spoken Japanese, given how many great audio resources there are online now. The challenge there is that there is a lot of slang, and its harder to find good online resources for the slang. If you want to learn to speak and write Japanese, then that's more difficult, and probably impossible, to accomplish through self-learning. You won't be able to reproduce intonation appropriately without practice speaking to someone who is already fluent in the language. Nor will you be able to pick up the social cues that tell you when to speak in formal, humble, casual, or informal register. However, I don't recommend trying to learn Japanese in Japan until you are up to an intermediate proficiency at least. There are many language schools for foreigners in Japan, but frankly it's expensive and you won't get that much out of a beginner course in Japan that you won't get from a beginner course or by self-learning at home. So my suggestion would be to take local/online courses or self-learn until you are roughly intermediate, then take language courses in Japan if you want to try to reach that upper Advanced/Fluent level.