Seongsu tonkatsu restaurant with free parking out front: Kosi Seongsu

Hi, I'm Younu :) Hope you're all having a good day! I came out to explore Ttukseom and Seongsu-dong in Seoul. Sightseeing is nice, but my main goal is always restaurant hunting — and I heard there was a Seongsu tonkatsu (pork cutlet) restaurant, a famous wait-in-line spot, specializing in cold udon and fresh loin tonkatsu, so I rushed over!

It's a restaurant that appeared on SBS's Life's Master, and actor Kim Seung-soo apparently raved about it after eating there. "Kosi Seongsu Branch." Let me share my own experience!

Kosi Seongsu Branch: location, hours and free parking

• Name: Kosi Seongsu Branch
• Hours: Daily 11:00–21:00
• Break time: 15:00–17:00
• Parking: 2 spots in front of the restaurant, free for 1 hour
• Seongsu Culture and Welfare Center public parking lot
• Seongdong-gu Sports Center public parking lot

Outside Kosi Seongsu Branch and the 1:30pm waitlist

Kosi Seongsu Branch is about a 1-minute walk from Ttukseom Station on Line 2, and about 5 minutes from Exit 1 of Seoul Forest Station. The exterior has a white-and-wood look.

I visited after 1:30pm to avoid the lunchtime peak, but there was still some waiting. If you want free parking, 2 spots in front of the restaurant offer 1 hour free. For nearby parking, the Seongsu Culture and Welfare Center or Seongdong-gu Sports Center public lots work well!

Since Kosi Seongsu Branch is a popular spot, you basically have to put your name on the waitlist as soon as you arrive :)! We did that right away, and didn't wait long before being seated.

Inside Kosi Seongsu Branch: is solo dining comfortable?

The inside of Kosi Seongsu Branch isn't huge. Since there are a lot of customers, there are quite a lot of staff too. It's an open kitchen, which honestly gave me more confidence in the food.

There are tables for 2 and for 4, which can combine into a group table for up to 8. There are also bar-style counter seats and window bar tables, so solo dining felt totally comfortable, no need to feel self-conscious. It was bustling even after 1:30pm, with a constant stream of waiting customers coming and going. Definitely a Seongsu hotspot.

The restroom is located outside the restaurant.

Kosi Seongsu Branch menu and what to order together

The menu was full of tonkatsu aged over 24 hours, hot udon, kama udon, cold udon, donburi (rice bowls), and side dishes! I ordered the mixed katsu set with tonkatsu and king shrimp katsu, a single order of tenbukka gake udon (cold udon) to beat the heat, and sweet potato cheese croquette with vegetable tempura.

• Tenbukka gake udon (single)
• Mixed katsu set
• Sweet potato cheese croquette & vegetable tempura
• Zero Coke

Such a hearty spread. The set portion is no joke, but the single order was also more filling than expected!

The udon and vegetable tempura that came as sides.

Ten bukkake udon: how are the Sanuki fresh noodles?

Beyond the cold udon itself, the big, crispy-looking sweet pumpkin and shrimp tempura on top really catch the eye! The tsuyu (dipping broth) is served separately, so you can adjust it to your own taste — such a nice touch!

Now let me build my own bowl the way I like it :)

The noodles seemed a bit thicker than regular udon, and they have real bounce to them. You can actually feel the chewiness while eating — that kind of chewy, satisfying bite. Since the process of making them is apparently complicated and time-consuming, the taste really matches the effort!

"Kosi" → chewy bite / having "koshi" → having that chewy bite, apparently!

The tenbukka gake cold udon tasted even better eaten in the hot weather. The broth was slightly salty in a way that kind of snaps you awake, and it was delicious!

Mixed katsu set: pork loin tonkatsu and king shrimp katsu

Now let me introduce the mixed katsu!

A thick, traditional-style cutlet! Probably because it's aged over 24 hours, the katsu was really tender. Crispy outside, juicy inside :) You can dip it in katsu sauce, or go with the wasabi-and-salt combo to fully taste its flavor!

As someone who loves katsu, I'd say Kosi could also earn its place as a katsu specialty restaurant?! If you love katsu, I'd recommend it — it's that good!

The inari sushi (fried tofu pouch rice) and vegetable tempura also came in generous, large portions.

The side dish: sweet potato cheese croquette

The sweet potato cheese croquette had cheese and sweet potato together inside, making it sweet yet really soft in texture. Crispy outside, tender inside, if you will! Also seriously delicious. If you need to pick a side, I'd recommend this one.

The giant king shrimp katsu.

The pork loin tonkatsu was already an art form, but the shrimp katsu was genuinely on another level. Normally when I eat katsu it's loin or fillet cuts, and the closest thing to a shrimp option is shrimp tempura as a side. But when I cut into the shrimp katsu to make it easier to eat, it turned out to be completely packed with a whole, plump shrimp...! How could that not be delicious. If you don't like fried batter, you could separate it out and eat around it. Dipping it generously in the shrimp katsu sauce brings out even more flavor.

My state after finishing all of this.

Is Kosi Seongsu Branch worth the wait? Final verdict

The Ttukseom–Seongsu area is somewhere I always wanted to visit when coming to Seoul — there's so much to see, and so many good restaurants and cafés! Visiting in person, there was a wait, but it wasn't too long, and it was worth it. If you look closely at the prices, there are quite a few reasonably priced options too, making it good for a simple meal and comfortable for solo dining.

Having tried both the katsu and the cold udon, I'd say they fry the katsu just as well as dedicated katsu specialty restaurants, and the cold udon, made with fresh noodles in the traditional Sanuki style, is really chewy with great bounce, plus a uniquely distinct soy-sauce flavor. If you like Japanese-style katsu and Japanese-style udon, I'd definitely recommend a visit, and if you're looking for good restaurants around Ttukseom or Seoul Forest, this one comes recommended!