The International Boys Nankyu Baseball Association Japan (I.B.A. Boys) () is a Japanese youth baseball organization involved in international exchange through rubber-ball baseball (nankyu baseball). The association is best known for organizing the International Boys Nankyu Baseball World Championship, an annual youth tournament held in Japan featuring teams from multiple countries.
The association was established in 1982 and has conducted international youth baseball exchange activities since its founding.
The association organizes international youth baseball tournaments and exchange programs involving teams from Japan and overseas.
Local media have reported on international exchange games involving teams associated with the organization, including matches with teams from countries such as Brazil and the Philippines.
The International Boys Nankyu Baseball World Championship is an annual youth baseball tournament organized by the association and held primarily in Tokyo. The tournament features participation from multiple countries and has been held regularly for several decades.
In addition to the international tournament, the association is also involved in domestic competitions that serve as qualifying events for participation in the world championship.
The association has been described in local media as facilitating international exchange through youth baseball and contributing to grassroots-level sporting and cultural exchange.