3nin Matsuri (三人祭; Three-Person Festival; pronounced さんにんまつり, Sannin Matsuri) was one of the 2001 Hello! Project Shuffle Units alongside 7nin Matsuri and 10nin Matsuri. The theme of the group was said to be "overwhelming cuteness".
- [2001.07.04] Chu! Natsu Party (チュッ！夏パ～ティ, Kiss! Summer Party)
- [2001.12.19] Hello! Project - Petit Best 2 ~3, 7, 10~ (#1 Chu! Natsu Party)
- [2008.12.10] Hello! Project - Hello! Project Shuffle Unit Mega Best (#4 Chu! Natsu Party)
- [2001.08.29] The 3, 7, 10nin Matsuri
- This group was the winner of the 2001 competition to see which of the shuffle units could sell the most copies of their single.