All 39 costumes of Arimura Mao in-game, with their unlock conditions — taken from the publisher's own released data (Costume.yaml).
GO MY WAY!!
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
SUGAR FLAVOR
Obtained by pulling Arimura Mao in the "SUGAR FLAVOR" gacha banner
SUGAR FLAVOR
Obtained when Arimura Mao ("SUGAR FLAVOR" version) reaches Talent Bloom stage 4
ENDLESS DANCE
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Look At Me (見て)
Obtained by pulling Arimura Mao in the "Look At Me (見て)" gacha banner
Look At Me (見て)
Obtained when Arimura Mao ("Look At Me (見て)" version) reaches Talent Bloom stage 4
Let's Charge Forward! (がむしゃらに行こう！)
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Miracle Nanau! (ミラクルナナウ(ﾟ∀ﾟ)！)
Obtained by pulling Arimura Mao in the "Miracle Nanau! (ミラクルナナウ(ﾟ∀ﾟ)！)" gacha banner
Miracle Nanau! (ミラクルナナウ(ﾟ∀ﾟ)！)
Obtained when Arimura Mao ("Miracle Nanau! (ミラクルナナウ(ﾟ∀ﾟ)！)" version) reaches Talent Bloom stage 4
Howling over the World
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
A Piece of Cake, Anytime Anywhere (古今東西ちょちょいのちょい)
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Cherry Blossom Photograph (桜フォトグラフ)
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
As the Snow Melts (雪解けに)
Obtained by pulling Arimura Mao in the "As the Snow Melts (雪解けに)" gacha banner
As the Snow Melts (雪解けに)
Obtained when Arimura Mao ("As the Snow Melts (雪解けに)" version) reaches Talent Bloom stage 4
Happy Millefeuille (ハッピーミルフィーユ)
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Campus mode!!
Obtained by pulling Arimura Mao in the "Campus mode!!" gacha banner
Campus mode!!
Obtained when Arimura Mao ("Campus mode!!" version) reaches Talent Bloom stage 4
White Night! White Wish!
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Costume Rhapsody (仮装狂騒曲)
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Feel Jewel Dream
Obtained by pulling Arimura Mao in the "Feel Jewel Dream" gacha banner
Feel Jewel Dream
Obtained when Arimura Mao ("Feel Jewel Dream" version) reaches Talent Bloom stage 4
Crowning Chrysanthemum (冠菊)
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
You and Semi-Blue (キミとセミブルー)
Obtained by pulling Arimura Mao in the "You and Semi-Blue (キミとセミブルー)" gacha banner
Fluorite
Obtained by pulling Arimura Mao in the "Fluorite" gacha banner
Fluorite
Obtained when Arimura Mao ("Fluorite" version) reaches Talent Bloom stage 4
Beginning (初（はじめ）)
Owned from the start
Gleam of Gold (ゴールドの輝き)
Clear Stage 10 of Arimura Mao's Path to Idol
Gleam of Platinum (プラチナの輝き)
Clear Stage 15 of Arimura Mao's Path to Idol
Gleam of Jet Black (漆黒の輝き)
Clear Stage 25 of Arimura Mao's Path to Idol
Favorite Casual Wear (お気に入りの私服)
Obtained as an event reward
Everyday Casual Wear (いつもの私服)
Owned from the start
The Real Me (ホントのボク)
Raise Arimura Mao's Affection Level to 10
Lesson Wear (レッスンウェア)Training Outfit
Owned from the start
Lesson Wear (レッスンウェア)Training Outfit
Raise Arimura Mao's Master Achievement to Rank 3
Hinamatsuri Kimono (ひな祭り着物)
Purchasable directly in the costume shop
Sailor Swimsuit (セーラーミズギ)
Purchasable directly in the costume shop
Hatsuboshi Academy Gym Uniform (初星学園体操服)Training Outfit
Purchasable directly in the costume shop
Hot Spring Swimsuit (温泉用水着)
Purchasable directly in the costume shop
Child Smock (チャイルドスモック)
Purchasable via a costume bundle pack (or other means)
