Japan’s culture is truly a boundless paradise for weebs. They’re so considerate that they’ve even set aside a day just for us, imouto (little sister) lovers! September 6 is Younger Sister Day in Japan, and we’re taking care of our imouto this week with all the best little sister cosplays.
From the most precious little sisters that deserve all the headpats, to the imouto that have us clearing our search histories, here are the best little sister cosplays for Imouto Day!
Shiro: Little Sisters and Shimapan!
Starting off today with a classic, it’s Shiro from No Game No Life. Although the series has long been memed by fans for the lack of a second season (ye of little faith!), the characters are still beloved. Shiro is the perfect, adorable little sister, especially with those sexy striped panties — and she makes a fierce queen of Elkia.
The J-List store has you covered for all No Game No Life products, including this sexy Shiro 1/7 Hot Spring Ver. Figure that has Shiro covered in sticky soap!
(Right) Moondays is a royal beauty in her cosplay.
(Right) Sakuyaya‘s Shiro is the perfect wake-up!
Illyasviel: Stay the Night with This Little Sister Cosplay
Although most of Fate/Stay Night is a death battle involving historical figures, the spin-offs give other characters their own chance to shine. Illyasviel von Einzbern is a yandere little sister character in the main series; however, in Fate/kaleid liner Prisma Illya, she stars as a magical girl, complete with a Cardcaptor Sakura-esque magical staff. Did we mention Prisma Illya also has some very raunchy yuri content?
(Right) Illya’s a naughty schoolgirl in Okita Rinka’s cosplay!
(Right) Hoshililly cosplays Illya’s beast mode!
Suguha/Leafa: SAO Little Sister Cosplay!
Whether you love or hate Sword Art Online, let’s agree that Kirito chose wrong. Why go for the fiery swordsman when your sexy little sister is right next door?! Okay, technically, they’re cousins, but Suguha still fits the imouto archetype, and that’s good enough for us! Suguha even conquered her fears of virtual reality to become the fairy Leafa and help fight alongside Kirito while he rescued his in-game wife. If that’s not true love, what is?
(Right) FoxyKimeSprite and her hand-made Leafa cosplay!
Kirino Kousaka: The Original Imouto of Our Dreams
In every sense, Kirino Kousaka from My Little Sister Can’t Be This Cute (also known as Oreimo) is the ultimate otaku imouto you’ve been dreaming about. A quintessential tsundere hiding her love for her brother, Kirino is everything you could ask for rolled into a pint-sized package!
If you love the characters from Oreimo and Eromanga-sensei, check out the hardcover artbook from the series character designer, Hiro Kanzaki!
(Right) RocksyLight with an irresistible little sister cosplay.
Kotori Itsuka: Date-a-Sis!
Have you ever wished your sister were the head of a secret organization dedicated to defending the world? If you checked “yes” to that specific question, then you’ll love Kotori Itsuka from Date-a-Live. Not only is she the feared commander of Ratatoskr, but she’s a fearsome Spirit to boot, with a tsundere personality that’ll always keep you on your toes!
(Right) Sally Teh with the cutest poolside Kotori!
Nezuko Kamado: Protect At All Costs!
Demonic little sister Nezuko comes in two flavors, making her a truly versatile imouto. When her big brother is in danger, Nezuko can unleash her true powers and tackle Muzan’s top lieutenants. For the most part, however, Nezuko is the sleepy little sister who deserves all the head pats in the world. Don’t forget to check out our Demon Slayer cosplay post ahead of Infinity Castle hitting cinema screens!
(Right) Aluctoria’s Nezuko has a cheeky panty flash!
Sagiri Izumi: My Little Sister Can’t Draw This Lewd!
What if your step-sister were a hikikomori who drew ecchi light novel illustrations? Sagiri Izumi from Eromanga-sensei is the second little sister on this list from author Tsukasa Fushimi (after Kirino from Oreimo). She’ll act innocent in real life, but draw the lewdest illustrations when she’s alone — and it’s this bashful personality that makes her perfect for little sister cosplay!
(Right) Murrning Glow gives us the cutest Sagiri.
(Right) SweetieLine bares all for her imouto cosplay!
Mikan Yuuki: To Love Your Little Sister
Sometimes you don’t want a clingy imouto, but more of a grounded anchor — especially in a series with harem antics and sci-fi chaos. Mikan adds some wholesome, “girl-next-door” energy to To LOVE-Ru’s cast of gals — but make no mistake, she’s still bringing the siscon energy, especially in To LOVE-Ru Darkness.
The J-List store has plenty of To LOVE-Ru products in stock, and of course, we have to recommend the Mikan Yuuki Nurse Cosplay figure, so that you can play “doctor” with the best little sister!
(Right) Hachi-chan’s Mikan is super sexy!
Yuki Suou: Every Morning Is Good With Imouto Cosplay
A newer imouto on our list is Yuki from Alya Sometimes Hides Her Feelings in Russian. Best known for spawning the “Good Morning, My Brother!” meme, this adorable pajama-wearing sis is the alarm clock we’ve been praying for. Yuki’s even a card-carrying siscon-lover herself — what more could you ask for?
(Right) Nessarose offers a playful Yuki!
(Right) Twoyun teases in this lewd bedroom cosplay.
Thanks for reading this article about little sister cosplay! Are you also a card-carrying imouto fan? Let us know what you think in the comments!
Let’s Chat
You made it to the end of this post! Thank you! As a token of our appreciation, enjoy an extra 5% off your next order when you use the code BLOG at checkout. Also, don’t forget to follow J-List on all our platforms!
- Twitter / X, where Peter posts anime booba for you
- Bluesky, where we post several times a day
- Facebook, where we used to share memes and discuss anime
- Discord, if you want to chat with other J-List customers of culture
Happy New Year from your Friend in Japan, J-List! We hope 2026 is a year of happiness and peace for you. To get things off right, we’re having a huge site-wide New Year’s Sale through Jan. 6, giving you 15$ off all in-stock products. Start browsing now!
![Sawaranaide Kotesashi Kun Episode 12 [END] Featured Image](https://blog.jlist.com/wp-content/uploads/2025/12/Sawaranaide-Kotesashi-kun-Episode-12-END-Featured-Image-750x536.jpg)
