All 39 costumes of Shiun Seika in-game, with their unlock conditions — taken from the publisher's own released data (Costume.yaml).
GO MY WAY!!
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Heartbeat Emotion (ときめきエモーション)
Obtained by pulling Shiun Seika in the "Heartbeat Emotion (ときめきエモーション)" gacha banner
Heartbeat Emotion (ときめきエモーション)
Obtained when Shiun Seika ("Heartbeat Emotion (ときめきエモーション)" version) reaches Talent Bloom stage 4
ENDLESS DANCE
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Let's Charge Forward! (がむしゃらに行こう！)
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Miracle Nanau! (ミラクルナナウ(ﾟ∀ﾟ)！)
Obtained by pulling Shiun Seika in the "Miracle Nanau! (ミラクルナナウ(ﾟ∀ﾟ)！)" gacha banner
Love & Joy
Obtained by pulling Shiun Seika in the "Love & Joy" gacha banner
Love & Joy
Obtained when Shiun Seika ("Love & Joy" version) reaches Talent Bloom stage 4
Howling over the World
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
A Piece of Cake, Anytime Anywhere (古今東西ちょちょいのちょい)
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Cherry Blossom Photograph (桜フォトグラフ)
Obtained by pulling Shiun Seika in the "Cherry Blossom Photograph (桜フォトグラフ)" gacha banner
Cherry Blossom Photograph (桜フォトグラフ)
Obtained when Shiun Seika ("Cherry Blossom Photograph (桜フォトグラフ)" version) reaches Talent Bloom stage 4
As the Snow Melts (雪解けに)
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Happy Millefeuille (ハッピーミルフィーユ)
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Campus mode!!
Obtained by pulling Shiun Seika in the "Campus mode!!" gacha banner
Campus mode!!
Obtained when Shiun Seika ("Campus mode!!" version) reaches Talent Bloom stage 4
The Hidden Me (カクシタワタシ)
Obtained by pulling Shiun Seika in the "The Hidden Me (カクシタワタシ)" gacha banner
The Hidden Me (カクシタワタシ)
Obtained when Shiun Seika ("The Hidden Me (カクシタワタシ)" version) reaches Talent Bloom stage 4
White Night! White Wish!
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Costume Rhapsody (仮装狂騒曲)
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Crowning Chrysanthemum (冠菊)
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
You and Semi-Blue (キミとセミブルー)
Obtained by pulling Shiun Seika in the "You and Semi-Blue (キミとセミブルー)" gacha banner
You and Semi-Blue (キミとセミブルー)
Obtained when Shiun Seika ("You and Semi-Blue (キミとセミブルー)" version) reaches Talent Bloom stage 4
Tame-Lie-One-Step
Obtained by pulling Shiun Seika in the "Tame-Lie-One-Step" gacha banner
Tame-Lie-One-Step
Obtained when Shiun Seika ("Tame-Lie-One-Step" 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 Shiun Seika's Path to Idol
Gleam of Platinum (プラチナの輝き)
Clear Stage 15 of Shiun Seika's Path to Idol
Gleam of Jet Black (漆黒の輝き)
Clear Stage 25 of Shiun Seika's Path to Idol
Favorite Casual Wear (お気に入りの私服)
Obtained as an event reward
Hatsuboshi Academy Uniform (初星学園制服)
Owned from the start
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 Shiun Seika's Master Achievement to Rank 3
Cherry Blossom Sailor (桜セーラー)
Purchasable directly in the costume shop
Sailor Swimsuit (セーラーミズギ)
Purchasable directly in the costume shop
Hoodie Swimsuit (パーカー水着)
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)
