The Pacific Nations Cup is an international rugby union competition held between Fiji, Samoa, Tonga, Canada, Japan and the United States.

The Pacific Nations Cup was funded as an International Rugby Board (IRB) tournament which was part of the $US50 million, three-year, global strategic investment programme launched in August 2005.

The competition was aimed at developing the Pacific rim sides in the second tier of the rugby countries: Fiji, Japan, Samoa and Tonga.

"The IRB Pacific 5 Nations is a tournament that will provide more certainty for Fiji, Japan, Samoa and Tonga in terms of regular high level Test match rugby, while also providing a high level of competition for the Junior All Blacks," said Mark Egan, the IRB's Head of Rugby Services.

Australia had been invited to take part in the inaugural 2006 tournament but decided against sending a team stating that they wanted to focus on their domestic competition.

The inclusion of Australia A meant that the tier 2 teams would have an even greater number of matches in the buildup to the 2007 Rugby World Cup.

In January 2013, the IRB announced that both the United States and Canada teams would be joining the 2013 competition on a permanent basis.

The sides from Canada, Japan and United States played in their respective regional qualifiers for the 2019 Rugby World Cup.

[5] For 2019, Canada, Japan and the United States returned to the tournament, serving as a prelude to the 2019 Rugby World Cup.