Zaru udon (cold udon) served on a bamboo mat with ice and maple leaves, accompanied by dipping sauce, wasabi, chopped scallions, sesame seeds, ginger, and shredded seaweed on small plates.

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Recipe Highlights

Growing up in Yokohama, cold noodle dishes were a household staple through the hot, humid summers. My mom served Zaru Udon (Cold Udon with Dipping Sauce) on the warmest days—thick noodles straight from the ice bath, a cup of cold dipping sauce on the side.

It was the simplest meal—and somehow the only dish that sounded good when the heat suppressed your appetite.

I still make it the same way today, and the only real decision is whether to make the dipping sauce from scratch or use a bottled mentsuyu as a shortcut.

Here’s why I keep coming back to this recipe:

  • Ready in 15 minutes, start to finish
  • Cool, savory, and light—perfect when you don’t have much appetite on a sweltering day
  • Dipping sauce two ways: from scratch or quick with bottled mentsuyu

If you love udon, try my Udon Noodle Soup, Beef Udon, and Yaki Udon (Stir-Fried Udon Noodles) next!

A plate of zaru udon (cold udon noodles) rests on a bamboo mat with ice cubes and green maple leaves, accompanied by chopsticks on a wooden table.

What is Zaru Udon (Cold Udon)?

Zaru udon (ざるうどん) is a Japanese cold noodle dish that takes its name from the zaru (bamboo strainer) traditionally used to drain and serve the noodles.

It originated as a way to beat the heat during Japan’s hot and humid summers, when appetite fades and cool food feels essential. Along with Zaru Soba, zaru udon remains one of the most popular warm-weather meals in Japanese homes and restaurants alike.

Ingredients for Zaru Udon (Cold Udon)

  • Udon noodles – frozen, parboiled, or dried
  • Green onion/scallion
  • Fresh ginger
  • Wasabi – optional
  • For the dipping sauce (tsuyu) – or use bottled mentsuyu for a shortcut (see Tips)

Find the printable recipe with measurements below.

Jump to Recipe

How to Make Cold Udon with Dipping Sauce

  1. Make the dipping sauce. Simmer dashi, mirin, and sugar over medium heat until the sugar dissolves. Add soy sauce, return to a simmer, then remove from heat. Cool completely over an ice bath.
  1. Cook the noodles. Bring a large pot of water to a boil. Add frozen noodles straight from the freezer and boil for 1 minute until heated through. For dried noodles, follow the package directions.
  1. Rinse and chill. Drain the noodles and rinse off excess starch under cold running water. Transfer to a bowl of ice water for 30–60 seconds, then drain.
  1. Prep the condiments. Thinly slice the green onion, and peel and finely grate the ginger. Arrange them on small plates alongside wasabi, if using.
  1. Assemble and serve. Divide the drained noodles onto individual plates alongside a few ice cubes. Pour the cooled tsuyu into dipping cups. Stir condiments into your sauce, dip the noodles, and enjoy.
A hand pours soy sauce from a small glass container into a saucepan with dashi stock on a stovetop—perfect for preparing dipping sauce for zaru udon (cold udon).
A stainless steel pot of boiling water with bundles of uncooked udon noodles being cooked, partially submerged and separating as they heat up—perfect for making zaru udon (cold udon) later.
A metal colander filled with zaru udon (cold udon) and ice cubes sits on a wire rack, cooling the noodles.
A person slices green onions on a wooden cutting board with a knife. The thin slices of green onion are scattered on the board near the person's hand, perfect for topping a refreshing bowl of zaru udon (cold udon).
A plate of zaru udon (cold udon) sits on a bamboo mat with ice cubes, garnished with maple leaves. Chopsticks rest nearby, and dipping sauce, green onions, wasabi, and condiments are arranged on a wooden table.
A hand uses chopsticks to dip thick zaru udon noodles, topped with sliced green onions, into a patterned cup of broth. A plate of cold udon noodles and garnishes sit on a wooden table in the background.
Namiko Hirasawa Chen

Nami’s Recipe Tips

Keep these tips in mind for the best results every time.

  • Make the dipping sauce from scratch – Homemade dipping sauce makes a noticeable difference in depth of flavor.
  • Use a shortcut sauce – Japanese households keep bottled mentsuyu on hand for exactly this. Dilute it with cold water, and you have a dipping sauce in minutes. See the recipe card below for details.
  • Cool the sauce completely – After simmering, I set the pitcher in a bowl of ice to bring it down fast. You can also make it a day ahead and refrigerate it so it’s chilled and refreshing.
Mentsuyu / Tsuyu (Japanese Noodle Soup Base) | Easy Japanese Recipes at JustOneCookbook.com
A glass measuring cup with dark liquid, perfect for dipping zaru udon (cold udon), sits in a metal bowl filled with ice on a wooden surface.
  • Use frozen udon – I reach for frozen Sanuki udon from the Japanese market—it has that thick, chewy pull I love. Shelf-stable dried udon noodles or vacuum-packed fresh udon noodles are a good alternative if you can’t find refrigerated or frozen.
  • Rinse the noodles thoroughly – Rinse the hot noodles under cold water, tossing with your hands as if washing clothes. This stops the cooking and rinses away excess starch, keeping the noodles firm and chewy rather than mushy while preventing clumping.
The packages include udon noodles.
A hand rinses and scrubs cooked udon noodles in a metal strainer under running water, preparing Zaru Udon (Cold Udon) in a kitchen sink.
  • Chill briefly, serve cold – Keep the ice bath to 30–60 seconds—any longer, and the noodles lose their signature chewy bite. Plate them with a few ice cubes to keep them cold and firm throughout the meal.
A plate of zaru udon (cold udon) served on a bamboo mat with ice cubes, chopsticks, and a green maple leaf garnish, set on a rustic wooden table.
Chopsticks hold zaru udon topped with green onion and seaweed, dipping them into a patterned bowl of sauce. Plates of more cold udon and toppings sit on a wooden table in the background.

Variations

Here are a few easy ways to make this dish your own.

  • Extra toppings. Shredded nori, tenkasu (tempura scraps), julienned shiso, and toasted white sesame seeds all make great toppoings for zaru udon.
  • Cold Tanuki Udon. Add tenkasu, sliced tomato, cucumber, wakame seaweed, and a soft-boiled egg for a more substantial bowl.
  • Cold Natto Udon. Top with fermented soybeans for a satisfying neba neba (ネバネバ, pleasantly sticky) texture—a beloved combination for natto lovers.
  • Cold Curry Udon. Ladle chilled curry soup over the noodles with sliced pork and seasonal vegetables for a heartier cold noodle bowl.
  • Vegan option. Swap the dashi for Vegan Dashi and skip the bonito flakes in the quick sauce. Everything else stays the same.
  • Fresh noodles from scratch. There’s nothing like slurping Homemade Udon Noodles. The texture is far superior to store-bought and well worth the effort—it’s easy and fun to make by hand.

What to Serve with Cold Udon

Zaru Udon pairs well with light, summery sides. Here are my picks:

  • Tempura – Cold noodles with crispy vegetable or shrimp tempura is called tenzaru udon (天ざるうどん). Read How to Make the Best Tempura for the batter and technique.
  • Green salad with Carrot Ginger Dressing– A light, refreshing side that balances the savory dipping sauce.
  • Mugicha (Japanese barley tea) – Chilled, earthy, caffeine-free—the quintessential Japanese summer drink for all ages.
Gluten Free Tempura | Easy Japanese Recipes at JustOneCookbook.com
White plates of fresh green salad with lettuce, cucumbers, radishes, and cherry tomatoes, topped with vibrant orange carrot ginger dressing and served with a gold fork on a marble surface.

Storage Tips

To store the dipping sauce, transfer leftover sauce to a clean, airtight container and refrigerate for up to a week. Cook the udon noodles just before serving—cooked noodles don’t hold well in the fridge.

FAQ

What is the difference between zaru udon and zaru soba?

Both are cold Japanese noodle dishes served with mentsuyu dipping sauce. Zaru soba uses buckwheat noodles, which have an earthy, slightly nutty flavor. Zaru udon uses thick wheat noodles with a chewy, neutral bite. The preparation and dipping sauce are nearly identical—it comes down to personal preference and which noodles you have on hand.

Can I use dried udon instead of frozen?

Yes. Shelf-stable dried udon noodles or vacuum-packed fresh udon noodles work fine—cook them according to the package directions, then rinse and chill the same way. For the dried noodles, the texture will be slightly thinner and less chewy than frozen Sanuki-style udon, but the flavor holds up well.

What is mentsuyu, and where can I buy it?

Mentsuyu is a concentrated Japanese noodle soup base made from dashi, soy sauce, mirin, and sugar. You dilute it with water before serving—dilution ratios vary by brand, so read the label. Look for it at Japanese grocery stores or order it online. If you prefer homemade, my tsuyu recipe in this post takes only a few minutes.

Can I make zaru udon ahead of time?

Make the dipping sauce up to a week ahead and keep it refrigerated. Cook the udon noodles just before serving—chilled cooked noodles clump together and lose their texture overnight.

Readers’ Zaru Udon

Zaru Udon was the JOC Cooking Challenge for June 2026. Check out the delicious dishes created by JOC readers!

Collage of 20 different udon noodle dishes, each served in a bowl or plate with various toppings and dipping sauces, accompanied by small side dishes, showing a variety of presentations and ingredients.

I’d love to hear how yours turned out! 💛 Please leave a star rating and comment below to share your experience. Your feedback not only supports Just One Cookbook but also helps other home cooks discover recipes they can trust.

Zaru Udon (Cold Udon with Dipping Sauce)

4.85 from 19 votes
by Namiko Hirasawa Chen
A plate of zaru udon (cold udon) sits on a bamboo mat with ice cubes, garnished with maple leaves. Chopsticks rest nearby, and dipping sauce, green onions, wasabi, and condiments are arranged on a wooden table.
Zaru Udon (Cold Udon) is a classic Japanese chilled noodle recipe of thick, chewy udon and a savory mentsuyu dipping sauce that you can make into a refreshing meal in just 15 minutes. Make dipping sauce from scratch or use my shortcut method. Serve the noodles chilled on ice with green onion, grated ginger, and wasabi on the side.
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Prep: 10 minutes
Cook: 5 minutes
Total: 15 minutes

Ingredients 
 

Servings: 2

For the Dipping Sauce (Tsuyu)

For the Classic Condiments

  • 1 green onion/scallion
  • wasabi
  • ½ inch fresh ginger (optional)

Instructions

  • Gather all the ingredients.
    This recipe makes homemade dipping sauce. To make a quick dipping sauce using bottled mentsuyu (concentrated noodle soup base), see my recipe Notes at the end.
    Cold Udon-step by step-2 Ingredients

To Make the Dipping Sauce (Tsuyu)

  • Add ⅔ cup dashi (Japanese soup stock), 2 Tbsp mirin, and 1 tsp sugar to a small saucepan. Bring to a simmer over medium heat, stirring until the sugar dissolves.
    Easy Mentsuyu 1
  • Add 2 Tbsp soy sauce. Bring it back to a simmer, then turn off the heat. Transfer to a heat-resistant container or serving pitcher and set in a bowl of ice to cool. This dipping sauce is ready to use; no need to dilute.
    Nami's Tip: Make it ahead and keep it in the fridge until ready to use (up to 1 week).
    Easy Mentsuyu 2

To Prepare the Noodles

  • Bring a large pot of water to a boil. Add 2 servings udon noodles (no need to defrost from frozen) and boil for 1 minute to heat through.
    Nami's Tip: I use my favorite frozen Sanuki udon from the Japanese market. Shelf-stable dried udon noodles or vacuum-packed fresh udon noodles are good alternatives; cook according to package directions.
    Two images: On the left, hands place a bundle of uncooked udon noodles into boiling water. On the right, chopsticks stir the noodles as they cook—steps in preparing fresh zaru udon (cold udon noodles).
  • Drain in a sieve. Thoroughly rinse off excess starch under running water using your hand until the noodles are no longer slippery. Place them in an ice bath to chill for 30–60 seconds—any longer and the noodles will become too firm.
    Two-panel image: On the left, a hand rinses cooked zaru udon under running water in a metal strainer. On the right, the cold udon sit in the strainer with ice cubes on top, chilling them.

To Prepare the Condiments

  • Cut 1 green onion/scallion into thin slices. Peel and grate ½ inch fresh ginger. Divide the sliced green onion, grated ginger, and wasabi onto small individual plates.
    Three-panel image: hands grating ginger, slicing green onions, and a small plate with grated ginger, wasabi, and chopped green onions—classic toppings for zaru udon (cold udon)—arranged neatly on a wooden surface.

To Serve

  • Drain the chilled noodles well. Divide onto serving plates with a few ice cubes and your choice of toppings (see notes). Pour the cooled tsuyu into individual cups, stir in the condiments, and dip the noodles to eat.
    Two images side by side: on the left, hands arrange zaru udon noodles on a bamboo mat; on the right, cold zaru udon is served with garnishes, dipping sauce, chopsticks, and side dishes nearby.

To Store

  • Cook the udon noodles just before serving. Store leftover dipping sauce in a clean, airtight container in the refrigerator for up to a week.

Notes

Quick Dipping Sauce (4 servings)
When I’m short on time, I make this quick tsuyu using store-bought mentsuyu:
  1. Add ½ cup bottled mentsuyu (concentrated noodle soup base), 1 piece kombu (dried kelp), and ½ cup katsuobushi (dried bonito flakes) to a measuring cup or container.
  2. Steep it in the fridge for at least 10 minutes (or up to overnight for more flavor).
  3. Strain through a sieve into a pitcher or other container.
  4. Add 1½ cups water * to dilute. Serve into individual dipping cups.
* The bottled mentsuyu I use is concentrated 3 times for cold noodle dipping sauce (“men no tsuketsuyu”), so I dilute it with three parts water (1:3). Follow your bottle’s instructions, as each brand is different. If you have “straight” mentsuyu, you don’t need to dilute it.
Variations
Here are a few easy ways to make this dish your own.
  • Extra toppings. Shredded nori, tenkasu (tempura scraps), julienned shiso, and toasted sesame seeds all work well on zaru udon.
  • Cold Tanuki Udon. Add tenkasu, sliced tomato, cucumber, wakame seaweed, and a soft-boiled egg for a more substantial bowl.
  • Cold Natto Udon. Top with fermented soybeans for a satisfying neba neba (ネバネバ, pleasantly sticky) texture that’s popular across Japan.
  • Cold Curry Udon. Serve in a chilled curry soup with sliced pork and seasonal vegetables for a heartier cold noodle bowl.
  • Vegan option. Swap the dashi for vegan dashi and skip the katsuobushi (bonito flakes) in the quick sauce. Everything else stays the same.
  • Fresh noodles from scratch. There’s nothing like slurping Homemade Udon Noodles. The texture is far superior to store-bought and well worth the effort—it’s easy and fun to make by hand.

Nutrition

Calories: 294kcal, Carbohydrates: 56g, Protein: 8g, Fat: 0.03g, Saturated Fat: 0.01g, Polyunsaturated Fat: 0.01g, Monounsaturated Fat: 0.01g, Sodium: 726mg, Potassium: 46mg, Fiber: 4g, Sugar: 6g, Vitamin A: 60IU, Vitamin C: 1mg, Calcium: 25mg, Iron: 1mg

The nutrition facts shown are generated by an online calculator and are estimates only. Please consult a professional nutritionist for specific dietary needs.

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Editor’s Note: This post was originally published on July 21, 2025, and republished with more helpful information on May 31, 2026.