Volunteer Spirit

 is a compilation box set released by Seifuku Koujo Iinkai, commemorating their twentieth anniversary. It is officially credited as SKi's 36th, 37th and 38th albums, collectively.

The box set consists of three CDs and one DVD.

CD 1: Kiyokuta Dashikuutsu Kushiku

 * 1) Prolouge (Josho) (プロローグ（序章）)
 * 2) Volunteer Spirit
 * 3) Kuroi Hitomi(Re-Recording)
 * 4) Ai to Yuki no Omoiyari
 * 5) Sayonara wa Deai no Ashita he no Shirushi
 * 6) Meguriai
 * 7) Emerald no Densetsu
 * 8) Jidai wa Circus no Zou ni Notte
 * 9) Kurukuru Handkerchief
 * 10) Namo Nakigoe ni
 * 11) Itsumo no Youni
 * 12) Kiyokuta Dashikuutsu Kushiku
 * 13) Chikyuu ni Ai wo
 * 14) Epilogue (Shuushou) (エピローグ（終章）)

CD 2: Ai to Yuki no Omoiyari

 * 1) Dokyusei
 * 2) Utakata no Yume
 * 3) LOVE×2
 * 4) Usagi-san no Koi Monogatari
 * 5) Nagai yo
 * 6) Kawattenai Wakattenai
 * 7) Seitansai no Uta
 * 8) SKi no Theme
 * 9) Deai
 * 10) Obaachan ga Suki
 * 11) Kimi to Kyuukyuusha
 * 12) SKi no Hashire! Eight Monday (SKiの走れ！エイトマンデー; SKi Runs! Eight Monday)
 * 13) Koi Seishun Shoujo
 * 14) Illumination
 * 15) Sono hi ga Kuru Made