Lemon Udon Recipe
Lemon Udon is a cold noodle dish featuring thinly sliced lemons over chewy Udon in the soup. The broth is light and refreshing — just tangy enough to cut through the summer heat, yet savory enough to leave you fully satisfied. If you’re looking for something that actually makes you want to eat on a brutal summer day, this is it.
What’s Lemon Udon?
Before Lemon Udon, there was Sudachi Udon. Strikingly similar in concept, Sudachi Udon actually carries a much longer history. It has deep roots as a regional dish of Tokushima Prefecture on Shikoku island, with a tradition that far predates its citrus cousin. Small and green, this citrus fruit may look like a lime, but it has a milder flavor than lemon and a distinctively delicate aroma. Sudachi itself is one of Tokushima’s most prized ingredients — the prefecture produces roughly 98% of Japan’s entire supply, making it an overwhelmingly dominant grower. For locals, Sudachi is less of a specialty item and more of an everyday condiment, so incorporating it into Udon was a completely natural fit. In Tokushima, Sudachi is squeezed over fish, stirred into hot pots, paired with sake, and worked into all kinds of dishes — Udon is simply another chapter in that long tradition. The visual of cold noodles blanketed in thin, jewel-like slices of Sudachi has also caught on as a social media favorite.
The coastal stretch of the Seto Inland Sea — which separates the mainland from Shikoku island — is Japan’s leading lemon-growing region, particularly in Hiroshima Prefecture and Ehime Prefecture. The mild climate and the reflected sunlight off the sea create ideal conditions for cultivation, and “Setouchi Lemon” has earned strong brand recognition across the country. Around 60% of all domestically grown lemons in Japan come from this area.
Also on Shikoku, Kagawa Prefecture — famously known as “Udon Prefecture” — was a natural partner for this nearby citrus bounty. It consistently ranks at the top nationally for Udon consumption per capita and is home to literally hundreds of Udon shops. Kagawa’s Udon culture has long embraced creative variety, hot and cold Bukkake Udon, so pairing local noodles with Setouchi lemon felt less like an innovation and more like an inevitability. Ehime Prefecture adds yet another layer to this story, sharing both a lemon-growing heritage and a thriving Lemon Udon culture of their own.
Together, these flavors and traditions have grown into a regional identity. Lemon Udon products are now sold as local souvenirs and specialty foods across Kagawa and Hiroshima, and Setouchi-themed restaurants and cafes have embraced it as a signature dish. From a locally-sourced food perspective, Udon made with homegrown lemons has become more than a meal — it’s a vehicle for regional pride and revitalization.
Tips and substitutions for Lemon Udon
- Feel free to swap in any local citrus you enjoy. Lemon is the most common choice, but the dish was born from using the fruit grows nearby — so there are no strict rules.
- Frozen Udon is highly recommended. It closely mimics the chewy, hearty texture of fresh Shikoku-style Udon, and chills beautifully. Keep it cold right up until serving.
- Cold temperature is key. The broth should be thoroughly chilled — making it earlier in the day and letting it rest in the fridge before dinner works well. You can add ice just before serving, but keep in mind it will dilute the soup over time.
- Want a little kick? A sprinkle of Shichimi pepper pairs very well with the lemon brightness.
More recipes like Lemon Udon
Video
Ingredients
- 2 servings udon noodles (frozen or dried)
- 1 green onion
Instructions
- Make the soup for the udon. Prepare dashi using katsuobushi (bonito flakes). Add salt, soy sauce, sake, and mirin, then bring to a boil for a couple of minutes. Remove from heat and let it cool.
- Thinly slice the lemons and add them to the soup. It’s fine to add them while the soup is still warm. Refrigerate until fully chilled.
- Just before serving, cook the udon noodles according to the package instructions. Drain and rinse under cold running water, then chill further with ice if desired. Finely chop the green onions.
- To assemble, place the noodles in a large bowl, pour the chilled soup over them, and top with lemon slices and green onions.
