If you’re craving something warm, satisfying, and full of umami, look no further than seaweed and seafood udon soup. This Japanese-inspired noodle soup combines the richness of the sea with the chewy comfort of thick udon noodles. It’s a dish that feels nourishing, light yet filling, and packed with depth in every spoonful.
The base of the soup is a gently flavored dashi broth. Traditionally made from kombu (dried kelp) and bonito flakes, this broth is subtle but deeply savory. It’s the perfect canvas for fresh seafood and delicate seaweed to shine. The broth can be homemade or store-bought, and adding a splash of soy sauce and mirin brings the flavor to life with a balance of salty and sweet.
Seafood options are flexible, so you can use what’s fresh or available. Shrimp, scallops, mussels, and small chunks of white fish are all excellent choices. They cook quickly in the hot broth, releasing their natural juices and infusing the soup with even more flavor. Adding wakame seaweed is key here. It softens as it simmers, adding a silky texture and a mineral-rich taste that complements the seafood beautifully.
Udon noodles are thick, slightly chewy, and incredibly satisfying. Whether you use fresh, frozen, or vacuum-packed noodles, they should be cooked separately and added to the broth just before serving. This keeps them from becoming too soft and allows you to control the final texture.
To finish, garnish the soup with sliced green onions, a soft-boiled egg, a few drops of sesame oil, or even a sprinkle of togarashi (Japanese chili powder) for a hint of heat. The result is a comforting bowl of soup that brings together the sea’s best ingredients in a way that’s both simple and elegant.
Seaweed and seafood udon soup is a great weeknight dinner or a soothing meal for when you want something wholesome and quick. With just a few ingredients and 20 to 30 minutes, you can enjoy a flavorful bowl that warms you from the inside out.
Ingredients
- 250 g udon noodles
- 200 g assorted seafood squid, and mussels), such as shrimp
- 2 sheets dried seaweed
- 4 cups stock vegetable or fish
- 1 onion thinly sliced
- 2 cloves garlic minced
- 1 tbsp soy sauce
- 1 tbsp mirin
- 1 tbsp sesame oil
- salt to taste
- Spring onions for garnish
Instructions
- In a large pot, bring water to a boil and cook the udon noodles according to the package instructions. Drain and set aside.
- In another pot, heat the sesame oil and sauté the garlic and onion until fragrant.
- Add the seafood and cook until they are slightly firm.
- Add the stock, soy sauce, mirin, and dried seaweed. Bring to a boil and let it simmer for about 10 minutes.
- Add the cooked udon noodles and let it simmer for another 5 minutes.
- Season with salt to taste.
- Serve hot, garnished with spring onions.
I messed up step 3—my seafood cooked too long and got chewy. The flavor still came through, but texture was off. Lower cook time helps!
The ingredient list says 200 g assorted seafood squid, and mussels), such as shrimp—like… did you mean squid *and* mussels? Either way I followed it loosely and it turned out alright.
The instructions were a bit confusing. What’s mirin? Will using just soy sauce work?
Seafood??? No way, I don’t eat fish! Gave it a try, but it’s not going to be a favorite.
I didn’t have mirin, so I used vinegar, and it still tasted good lol.
Glad you enjoyed it! Vinegar is a good substitute, who knew? 😂
I dunno about that. Isn’t vinegar too strong? I always thought mirin was sweet.
Wow. Seaweed in soup is underrated. The sesame oil and garlic/onion combo made my kitchen smell amazing. Will make again for sure.
Yum! Best meal ever! I added some extra shrimp though, family loved it!
Wow, extra shrimp sounds great! I’ll have to try that next time! 🦐
My kids loved this! Easy and fun to make. Will make again for sure!
That’s awesome to hear! It’s great when you can get the kids involved in cooking too! 😊
Took me too long to cook the noodles. Is udon even supposed to take that long?
This soup is a total game changer! So comforting and hearty! I doubled the seafood.
I made it for my family and they liked it, but my brother said the noodles were ‘a little too bouncy’ lol. I think I should simmer them less after adding.
The recipe says ‘assorted seafood squid, and mussels), such as shrimp’—that punctuation is chaos 😅 Still, flavors sound legit.
Haha yes, that punctuation is definitely doing the most 😅 But I agree—the combo of seafood + seaweed + udon sounds really legit.
Too complicated for me. Like, I’m not measuring soy sauce, mirin, sesame oil, salt… I’ll just buy ramen 😅
Who knew you could make something so good with just noodles and sea stuff?😲
I didn’t have dried seaweed sheets so I used what I had (nori packs) and… it worked, but the texture was different. Also my mussels took longer than expected.
Recipe looks easy, but I think it’s too fancy for me. I prefer simpler things like ramen or instant.
Udon soup should not have seafood! That’s not how it’s done in my country. Just stick to traditional recipes, please.
Seafood is really good! Will make again for sure. Yum!
Why use udon? Just get ramen or something else! Udon isn’t right for this.
I dunno, the seaweed was kinda slimy for me. I guess it’s just not my thing.
I totally get you! Seaweed can be kinda weird texture-wise. Have you tried it in other dishes? Maybe it’s just not your flavor.
Noodle soup – yum! Has anyone tried this with extra veggies? Just curious!
Hmm, extra veggies? I dunno, aren’t the seafood the main thing in this? But you do you!
I added broccoli and carrots last time. It was great! Really brought it up a notch.
This sounds really comforting—seaweed + udon is such a good combo. The mirin and soy should make it taste super cozy. I’ll probably add a squeeze of lime too!
This soup is absolutely delicious! The combination of seafood and seaweed is so flavorful. Definitely a keeper! 👍
My noodles always turn mushy if I simmer too long, so I’d probably warm them off-heat. But overall sounds tasty.
This sounds like such a cozy bowl. I love that you used both seaweed and seafood—definitely the umami factor. I might add a pinch of chili too.
So bland!! Where’s the flavor? I added hot sauce just to spice it up. Never again. 🤷♂️
Made this tonight and it’s genuinely cozy. The seaweed really rounds out the broth, and the mirin gives it a nice little sweetness. I used shrimp + mussels and it turned out great.
I didn’t have any seafood so I just used chicken instead. Still came out delish!
I was skeptical about the seaweed, but it really adds a nice touch. Surprised me!
Seaweed? Really? I thought it would ruin the soup! But maybe I’ll give it a shot. Thanks for sharing your thoughts!
I like the simplicity, but 10 minutes might overcook the seafood depending on what you use. I’d add delicate stuff later.
Absolutely loved this recipe! The flavors were amazing, especially with the seafood. Will be making it again for sure!
The ingredient list says ‘1 onion thinly sliced’ but I also added some ginger because I felt like it. Turned out awesome. This is a flexible recipe.
This was surprisingly comforting. The seaweed gave it a nice depth and the udon stayed chewy like it should. I used a fish stock and it tasted super “restaurant-y.”
This soup was incredible! So rich in flavors, and the seafood was cooked perfectly. Will definitely make again!
I’m not that good in kitchen but this was easy to follow. Yay for me!
My seafood got overcooked a little—should’ve cooked it shorter. But the broth still tasted great. I’ll definitely make it again with better timing.
I found this a bit bland, even after adding extra soy sauce. Maybe next time I’ll add more spices.
I totally get what you mean! Sometimes a recipe just needs a little extra oomph. Maybe try some chili flakes or ginger next time for a kick!
I was skeptical about the dried seaweed but WOW. Next time I’ll slice the onion a bit thinner, because mine was a little chunky. Still delicious though.
Glad it worked out! Dried seaweed can be surprisingly awesome in udon—slicing the onion thinner is such a good tweak. 😄
Pretty good, but 10 minutes simmer for seaweed feels short/long depending on brand. I think mine needed a couple extra minutes—flavor was a tad mild at first.
Mine turned out a bit salty—probably I didn’t measure the soy sauce carefully. Also, I couldn’t find dried seaweed sheets so I used flakes. Still tasty though.
Yum! But I replaced seafood with chicken. Still taste good!
Interesting swap! Chicken must give it a different flavor. I’m curious to try it your way!
Chicken in a seafood recipe? That’s kinda weird… but if it tastes good, who am I to judge?
Why use seafood when you can just do chicken? 🤷♂️ Just saying.
But seafood adds a whole new flavor! Chicken just doesn’t cut it. 😋
yum! it was super tasty! But I forgot to add the mirin. Still turned out great! LOL.
Seaweed and seafood? Lol, sounds weird but I tried it and wow! Never thought I’d like seaweed! 🍜
So good! I didn’t have udon noodles, so used spaghetti. Still tasted great!!
Super easy recipe, loved it! My kids even ate the seaweed, which was a surprise.
Really? Kids eat seaweed? My nephew won’t even touch it! But I guess it’s just about how you serve it.
That’s awesome! Seaweed is so good for kids, it’s great they liked it! Did you add any extra veggies?
This soup is amazing! Just made it and my family loved it. The flavors are so good together! Definitely a keeper!
Wow. This tastes like something from a little ramen shop. The garlic-onion base is everything. Will definitely cook again.
I accidentally used vegetable stock and it tasted kinda flat until I added extra soy sauce. Once adjusted, though, it was really good!
Not gonna lie, I was skeptical about seaweed in a seafood soup, but it worked. The garlic/onion base is doing a lot of heavy lifting.
Too salty for my taste. I suggest reducing the soy sauce. Just my opinion.
I made this for my family and they all loved it! I added some chili flakes for an extra kick. Will make again!
Sounds delicious! Adding chili flakes is a great idea. I might try that next time. Glad your family loved it!
I followed it and it turned out bland until I added extra soy sauce. Then it finally popped. Maybe my stock was weak?
Huh, I think your measurements are off. 1 tbsp soy sauce for 4 cups seems too little, especially with udon. Also seaweed sheets vary a lot—mine were stronger, so yours might’ve been mild. Try more soy sauce or add a pinch of MSG if you have it.
Totally makes sense—if the stock was light or the seaweed didn’t fully hydrate, it can taste flat. Soy sauce + salt really is the missing punch for a lot of people. Next time maybe let it simmer the seaweed a few minutes longer before adding noodles.
This looks so cozy—seaweed + udon is such a good combo. I’m definitely trying this with shrimp and mussels next week!
Honestly, I didn’t taste much seaweed. Maybe my dried sheets were old or I didn’t simmer long enough. Still a decent seafood udon soup.
Eh, it was okay. I thought the broth would be tastier. Next time I’ll add some ginger.
I tried it but it just tasted too salty. Also the sesame oil is overpowering if you’re not careful. Maybe use less or add salt last.
Yum! I never had seaweed in soup before, but it was delish. My kids even ate it! A win in my book.
I had trouble finding the seaweed… Can I use something else? Not sure if it’ll taste the same.
Way too salty for me even with careful tasting. I’d reduce soy sauce or use low-sodium. Otherwise good flavor profile.