The 2021 Pacific Four Series was the first edition of the Pacific Four Series. The soft launch of the competition involved only Canada and the United States contesting two matches in Glendale, Colorado. The winner would be determined on aggregate score. Canada won the two matches on an aggregate of 22–41.
Australia and New Zealand were initially confirmed to join the competition, but because of the COVID-19 pandemic, World Rugby decided to go ahead with the soft launch with Australia and New Zealand joining in 2022.