Seongsu tonkatsu restaurant, weekend lunch with cheese croquette: Kosi

A Seongsu tonkatsu review — a date with my daughter at Kosi Seongsu Branch.

On a Saturday afternoon, my daughter and I went on a Seongsu date. :) When I asked what she wanted for lunch, the answer was — of course — tonkatsu! So without a second thought we headed to Kosi Seongsu Branch, a Seongsu tonkatsu spot.

Actually this isn't our first Kosi visit. We once went with the whole family to the Konkuk branch and tried everything from tonkatsu to udon, and it was delicious then. Since I'd already confirmed the taste, this time I went without hesitation. :)

How to get to Kosi Seongsu Branch, and where to park

Kosi Seongsu Branch is about 1 minute from Ttukseom Station Exit 6, and about 5 minutes from Seoul Forest Station Exit 1. It's a great stop if you're hanging out in Seongsu, or a good option when looking for a place to eat during a Seoul Forest date.

If you're driving, up to 2 cars can park in front for 1 hour free, and if that's full, you can use nearby lots like the Seongsu Culture & Welfare Center public parking.

Is there a wait at Kosi Seongsu Branch on Saturday lunch?

We visited during Saturday lunch hour. I expected some wait since it's Seongsu on a weekend, but luckily we got seated right away with no waiting. Still, true to weekend lunch form, the place was pretty full of customers.

Customers finishing up and new ones coming in kept the tables turning over fairly quickly. We got in right away, but I imagine there could be a wait depending on the time on weekends.

Smaller than the Konkuk University branch, but the cozier room

Compared to the Konkuk branch I visited before, Kosi Seongsu Branch is a bit smaller. But honestly, I liked the Seongsu branch's atmosphere even more.

It's a cozy, compact space done up in wood tones — felt more like a cozy little Japanese diner. :) Besides tables, there are bar seats too, which looked great for solo diners.

While we were eating, I saw staff quickly set up a baby chair for a family who came in with a young child. Tonkatsu is one of the top go-to dishes when eating out with kids, right? Haha. With baby chairs ready to go, this also looked like a solid Ttukseom restaurant to visit with young children.

Kosi Seongsu Branch menu and prices

Tonkatsu

• Tonkatsu single ₩11,500 / set ₩15,000
• Assorted katsu single ₩14,500 / set ₩18,000
• King shrimp katsu single ₩12,000 / set ₩15,500
• Cheese katsu single ₩12,500 / set ₩16,000
• Half-and-half katsu single ₩13,500 / set ₩17,000

Hot udon

• Kake udon single ₩9,000 / set ₩14,000
• Chicken tempura udon single ₩11,000 / set ₩16,000
• Shrimp tempura udon single ₩11,000 / set ₩16,000
• Fish cake udon single ₩11,000 / set ₩16,000
• Pork udon single ₩11,500 / set ₩16,500
• Kitsune udon single ₩11,000 / set ₩16,000

Kama udon and maze udon

• Kama bukkake udon single ₩9,000 / set ₩14,000
• Kama chicken tempura bukkake udon single ₩11,000 / set ₩16,000
• Kama tempura bukkake udon single ₩11,000 / set ₩16,000
• Maze udon single ₩11,000 / set ₩16,000

Donburi rice bowls

• Katsudon single ₩11,000 / set ₩14,500
• Beef rice bowl single ₩10,500 / set ₩14,000
• Karaage rice bowl single ₩10,500 / set ₩14,000

Cold udon and soba

• Bukkake udon single ₩9,000 / set ₩14,000
• Chicken tempura bukkake udon single ₩11,000 / set ₩16,000
• Tempura bukkake udon single ₩11,000 / set ₩16,000
• Zaru udon single ₩9,500 / set ₩14,500
• Zaru soba single ₩10,500 / set ₩15,500

Sides

• Sweet potato cheese croquette 2pc ₩3,500
• Fried squid rings 3pc ₩4,000
• Lotus root kushikatsu 3pc ₩4,000
• Vegetable tempura 1pc ₩2,000
• Extra tonkatsu (120g) ₩6,000

Drinks and alcohol

• Chamisul soju ₩5,000
• Cass (330ml) ₩3,500
• Asahi (330ml) ₩6,000
• Kirin (330ml) ₩6,000
• Pepsi Zero ₩2,000
• Coca-Cola ₩2,000
• Sprite ₩2,000

Kosi's signature isn't just tonkatsu — it's also known for fresh udon noodles made Sanuki-style. The noodles are made from salt, water and flour, aged in two stages, and take 48 hours to finish. So if you come to this Seongsu tonkatsu spot and only order tonkatsu, you'd be missing out! We ordered two things: half-and-half katsu and bukkake udon.

Half-and-half katsu: plain and cheese tonkatsu on one plate

The main dish for my katsu-craving daughter was Kosi Seongsu Branch's half-and-half katsu (₩13,500 single). It comes with regular tonkatsu and cheese tonkatsu together, so you get two flavors at once.

Thick tonkatsu with a thin, crispy coating, plus the cheese-filled tonkatsu — it was fun alternating bites between the two. They use domestic fresh pork loin, pounded daily and fried fresh to order.

Same as the delicious memory from the Konkuk branch — this time was just as good.

Bukkake udon: chewy cold fresh noodles

Coming to Kosi, you can't skip the udon either. We picked the bukkake udon (₩9,000 single).

The noodles look fairly thick and bouncy even in photos, but eating them makes the chewy, springy texture even more obvious.

It's served cold, so alternating bites with the crispy fried katsu worked really well. We came for tonkatsu, but the distinct fresh-noodle texture made me want to recommend it to anyone looking for a Seongsu udon spot too.

The sweet potato cheese croquette from the review event

We also took part in a review event and got a sweet potato cheese croquette.

Crispy fried outside with sweet potato and cheese inside — my daughter and I cleaned it up to the last bite. The result? We walked out patting our full bellies, and ended up skipping dinner that night. Haha. Between the half-and-half katsu, bukkake udon and croquette, it was genuinely filling for the two of us.

Practical notes before visiting Kosi Seongsu Branch

• About 1 minute walk from Ttukseom Station Exit 6
• 2 free parking spots in front, 1 hour free
• Possible wait on weekends depending on the time
• Baby chairs available, kid-friendly
• Recommend ordering tonkatsu and fresh udon together

Worth it? Kosi Seongsu Branch as a meal stop on a Seongsu day out

Thanks to good memories from the Konkuk branch, I went back to Kosi Seongsu Branch without hesitation. It's smaller than the Konkuk location, but the Seongsu branch's cozy, compact atmosphere personally won me over more.

Above all, the charm of Kosi is being able to enjoy the half-and-half katsu made with fresh pork loin — both regular and cheese tonkatsu in one — together with the chewy fresh-noodle bukkake udon.

It's close to Ttukseom Station and walkable from Seoul Forest, so if you're looking for a place to eat during a Seongsu date, or a Seongsu tonkatsu spot to visit with your kid, it's worth a stop. My daughter and I left full and happy once again. :)