What Japanese animation was the first to be an international success? Around 1910, I believe Japan started to experiment with animations and over a span of several decades anime became as we know it now. With hundreds of anime that became quite popular even outside of Japan, including off course the big shots such as One Piece and Naruto.

But which anime/ Japanese animation was the first to actually be successfully received outside of Japan?
A good guess is probably Katsuhiro Otomo's Akira. It was released in 1988 and had a worldwide theatrical release in more than 10 countries and at least 9 languages.

The Akira wiki page notes:


  The title has been regarded as one of the greatest animated movies of all time and prompted an increase in popularity of anime movies in the US and, generally, outside of Japan. It is still admired for its exceptional visuals. In Channel 4's 2005 poll of the 100 greatest cartoons of all time featuring both cartoon shows and cartoon movies,


and


  The film led the way for the growth of popularity of anime outside of Japan. Akira is considered a forerunner of the second wave of anime fandom that began in the early 1990s and has gained a massive cult following since then. Akira has also been cited as a major influence on live-action films ranging from The Matrix to Chronicle.


The History of Anime wiki page also notes:


  Despite the failure of Akira in Japan, it brought with it a much larger international fan base for anime. When shown overseas, the film became a cult hit and, eventually, a symbol of the medium for the West.


More info:


The Guardian - Akira: the future-Tokyo story that brought anime west
Anime News Network.




There was some mention of Dragonball, but the first of those movies were released in 1986 and none of the first ones had international releases.