Baby-friendly tonkatsu lunch with lotus root kushikatsu: Kosi Seongsu
In short
Kosi Seongsu Branch is a Japanese restaurant in Seongdong, Seoul, serving Sanuki self-made udon noodles and fresh loin tonkatsu. Visiting for lunch with a 17-month-old, the writer ordered half-and-half loin katsu, mini Sanuki kake udon, lotus root kushikatsu and squid rings, praising staff who brought baby tongs and scissors without being asked. It's a great waiting-line spot to stop with a toddler before a walk in Seoul Forest.

Good to know
- Location
- 31 Sangwon1-gil, 1F, Seongdong-gu, Seoul (closest to Ttukseom Station; Seoul Forest and Seongsu stations also walkable)
- Hours
- Daily 11:00–21:00 (break time 15:00–17:00)
- Parking
- 2 free parking spots at the restaurant
- Kids
- Baby-friendly / baby chair available / stroller accessible
- Half-and-half loin katsu
- ₩13,500
- Mini Sanuki kake udon
- ₩3,500
- Lotus root kushikatsu
- ₩4,000
- Squid rings
- ₩4,000
- Cola
- ₩2,000
- Udon set meal
- from ₩9,000
as written by the visitor on Sep 7, 2026
Chomp chomp chomp ๑◕‿‿◕๑
A tonkatsu place with a waiting line? Yes — Kosi, a well-known tonkatsu restaurant in Seongsu, is exactly that.
Here you can enjoy handmade self-milled Sanuki noodles, crispy fresh loin tonkatsu, and even lotus root tempura. Let me introduce Kosi Seongsu Branch, a favorite of my 17-month-old.

Kosi Seongsu Branch: location and hours
Kosi 📍31 Sangwon1-gil, 1F, Seongdong-gu, Seoul ⏰Daily 11:00–21:00 (break time 15:00–17:00) 🚘2 free parking spots at the restaurant ✨A Seongsu tonkatsu favorite recognized by 'Masters of Life' for its traditional Sanuki self-made noodles and outstanding crispy fried dishes 👼🏻Baby-friendly / baby chair available / stroller accessible
September — such lovely weather for a walk in Seoul Forest. Before heading there with my 17-month-old Hajun, we stopped by Kosi, a Seoul Forest tonkatsu favorite. Kosi is walkable from Seoul Forest, Seongsu, and Ttukseom stations, with Ttukseom being the closest.



Why it's famous for self-made Sanuki noodles
Kosi Seongsu Branch is directly operated by the Konkuk University main branch. Kosi is such a well-known tonkatsu and udon spot with waiting lines that it's famous throughout the area. To make the 800-year-old traditional Sanuki noodles, Kosi mills and makes its own noodles in-house. Because the noodle-aging process goes through many steps, every dish is full of care.




Kosi's crispy fried dishes are also outstanding — not just the fresh loin tonkatsu, but the lotus root tempura and squid tempura are really delicious too. My 17-month-old is at the age where she loves tonkatsu dishes, so on high-activity days, it's our number one pick for eating out.


Great for babies — they even give you tongs with the baby utensils
Kosi, a Seongsu tonkatsu favorite, also provides baby tableware, and I was so grateful they brought out tongs and scissors first thing. Usually places only give you a spoon, fork, and cup, and you have to ask for scissors separately. But giving tongs too — that kind of thoughtfulness is really... ♥ one of a kind.

When you have the kushikatsu udon or tonkatsu, salad sauce, sesame seeds, and seasoning powder are all set out on the table, so enjoy the different flavors.
What we ordered and the prices
- Half-and-half loin katsu ₩13,500
- Mini Sanuki kake udon ₩3,500
- Lotus root kushikatsu tempura ₩4,000
- Squid rings ₩4,000
- Cola ₩2,000

Reasonable prices for tonkatsu, right? Even just the thick, crispy lean loin katsu with the cheese-stuffed mozzarella katsu is ₩13,500, and you can add the handmade self-made Sanuki udon as a set for ₩3,500.


Lotus root kushikatsu, held and eaten by the 17-month-old herself
Whenever I stop by Kosi, I always order the lotus root kushikatsu (skewered fried dish). Kushikatsu is a Japanese-style fried dish skewered on a stick before frying — most Japanese tonkatsu restaurants don't even have kushikatsu on the menu, and lotus root tempura is unusual too. Kosi's lotus root tempura, a signature of this Seongsu tonkatsu favorite, has a bit of cheese mixed into the lotus root, so my 17-month-old absolutely loves it. It's one of the fried foods she can pick up on the skewer and eat herself, so I always order the lotus root kushikatsu at Kosi.


Whenever she eats well, I'm always cheering inside. Internal hoooray!



How the half-and-half loin katsu and mini kake udon taste
Kosi's tonkatsu stays crispy, so it's a no-regrets kind of taste. Udon is the signature item, but the tonkatsu dishes are delicious too, which is why it's always a waiting-line restaurant. Even past the lunch peak hours, there are always plenty of customers here — this is the kind of place where you eat after waiting in line.
And finally, the handmade Sanuki noodle kake udon appears. The noodles are chewy and plump with every bite. Not the kind that goes soft and loose in texture, but the kind with real density and a satisfying chew. Udon dishes start from ₩9,000 as a set meal, so try one if you stop by Seongsu. What's more, the udon we ordered as part of the tonkatsu set meal was ₩3,500 but still a decent portion. Eating it together with the tonkatsu, I just kept thinking how full and satisfied I felt.


The broth is simmered thoroughly with plenty of South Sea anchovies and kelp, so it's genuinely delicious. If the udon broth had been flavored with seasonings, I wouldn't have fed it to my child, but I could feed her the udon broth with total peace of mind, and we ate together happily. Between feeding her and eating myself, I was a bit frazzled, but she still fed a bite of tonkatsu into my mouth — such a sweet gesture, you know? This is the taste that makes parenting worth it.


In-season squid rings
The squid used in the squid tempura is fresh, in-season squid these days, so it's chewy with a great squid flavor, and I enjoyed it a lot. Dipped generously in mayo sauce too! All the fried dishes at Kosi are delicious, so it's always nice to come back.

Dipped in tonkatsu sauce, salt, and wasabi for a variety of flavors — Kosi, a tonkatsu favorite near Ttukseom Station. A cozy little date lunch with my 17-month-old, and such a satisfying meal — what a heartwarming day ♥ If you're stopping by Seongsu or Seoul Forest, be sure to visit with your little one.
Where it is
31 Sangwon1-gil, 1F, Seongdong-gu, Seoul, South Korea서울특별시 성동구 상원1길 31 1층










