Japanese Potato Salad

Creamy, Tangy, and Meant to Be Eaten Cold

Japanese potato salad shows up in bento boxes, at summer picnics, and next to fried foods like tonkatsu and karaage. It looks familiar at first glance — potatoes, mayo, a few crunchy vegetables — but the texture sets it apart. The potatoes are mashed while they're still hot, just enough to break down the edges, then folded with crisp cucumber, sweet carrot, and savory ham. A splash of rice vinegar while the potatoes are warm gives it a gentle tang that American-style deli salad usually gets from mustard alone.

That warm mash step is the whole trick. If you toss cold cubed potatoes with mayo, you get chunks in dressing. If you season and partially mash hot potatoes first, the dressing soaks in and the salad stays creamy after it chills.

The Ratios That Make It Taste Right

For 4 servings as a side, start here and adjust the mayo by the spoonful after chilling. Cold potatoes taste less seasoned than warm ones, so the salad should taste a touch bold right after mixing.

If you keep Kewpie on hand for other Japanese dishes, this is the place it earns its keep. Our Classic Miso Soup is the kind of light, brothy bowl that often shares a tray with this salad in a home-style set meal.

Ingredients

For the potatoes

• 1 1/2 lb (680 g) waxy or all-purpose potatoes, such as Yukon Gold, peeled and cut into 1 1/2-inch chunks
• 1 tablespoon unseasoned rice vinegar
• 1 teaspoon granulated sugar
• 3/4 teaspoon fine sea salt, plus more for the cooking water

For the mix-ins

• 1 small Japanese or Persian cucumber (about 4 oz / 115 g), thinly sliced into half-moons
• 1/4 teaspoon fine sea salt, for salting the cucumber
• 1 small carrot (about 2 oz / 55 g), peeled and cut into thin quarter-moons
• 2 slices deli ham (about 2 oz / 55 g), cut into 1/2-inch squares
• 1/4 small yellow onion, very thinly sliced
• 1/3 cup (80 ml) Kewpie mayonnaise, plus more to taste
• 1/4 teaspoon freshly ground black pepper
• 1 teaspoon yellow mustard (optional, for a sharper edge)

Prep: 20 minutes. Cook: 15 minutes. Total: 35 minutes, plus at least 30 minutes chilling. Serves 4 as a side.

How to Make It, Step by Step

1. Salt the cucumber first. Put the cucumber slices in a small bowl, toss with 1/4 teaspoon salt, and set aside for 10 minutes. This draws out water so the salad doesn't turn soupy in the fridge. Squeeze the slices gently with your hands and pat dry before using.

2. Cook the carrot briefly. Bring a medium pot of salted water to a boil. Add the carrot and cook 1 to 2 minutes, until just tender at the edges but still firm in the center. Lift it out with a slotted spoon and spread it on a plate to cool. Keep the water boiling for the potatoes.

3. Boil the potatoes until just tender. Add the potato chunks to the same pot. Cook 10 to 12 minutes, until a knife slides in with slight resistance — they should be cooked through but not falling apart. Drain well and return them to the warm, empty pot for 1 minute to steam off surface water.

4. Season and mash while hot. While the potatoes are still steaming, sprinkle the vinegar, sugar, and 3/4 teaspoon salt over them. Use a potato masher or a large fork to mash about half of the potatoes, leaving the rest in soft chunks. The mixture should look rough and creamy at the edges, not like mashed potatoes.

5. Cool before the mayo goes in. Spread the potatoes in a wide bowl and let them cool 10 minutes, until warm but no longer steaming. Mayo stirred into piping-hot potatoes can separate and taste greasy.

6. Fold everything together. Add the squeezed cucumber, carrot, ham, onion, mayonnaise, black pepper, and mustard if using. Fold gently with a spatula so the chunks stay intact. Taste and add salt or another spoonful of mayo if it seems dry.

7. Chill, then taste again. Cover and refrigerate at least 30 minutes, or up to overnight. Cold dulls salt and vinegar, so taste again before serving and add a pinch of salt or a few drops of vinegar if it needs lift.

Serve cold, scooped with a spoon so the soft edges stay visible. For a bento-style plate, pack it next to something crisp and hot. If you're building a Japanese home-style spread, our Japanese Cucumber Sunomono offers a lighter, vinegared cucumber to contrast the creamy potatoes.

How It Differs from American Potato Salad

The two salads start from the same idea and land in different places. Most American deli versions keep the potatoes in firm cubes and lean on celery and mustard. The Japanese version mashes part of the potato, uses thinner-sliced vegetables, and favors Kewpie's egg-yolk richness with rice vinegar instead of a heavy mustard bite. Ham is common in Japan; diced egg shows up in both traditions.

If you want the crunchier Korean-leaning cucumber side instead, our Oi Muchim is spiced and sesame-forward, a different kind of cold side for the same table.

Tips for a Salad That Stays Creamy

• Don't overboil the potatoes. Mushy potatoes turn the whole bowl into mash. Start checking at 10 minutes and drain as soon as they're tender.
• Dry the cucumber well. Salted cucumber that goes in wet will weep in the fridge and thin the dressing overnight.
• Season in two stages. Vinegar and salt on the hot potatoes, then salt and mayo again after chilling. That layering keeps the flavor from disappearing when cold.
• Slice the onion very thin. Thick onion overwhelms this salad. If your onion is harsh, soak the slices in cold water for 5 minutes and pat dry before folding in.
• Use Kewpie if you can find it. Its yolk-only richness and mild sweetness are hard to swap exactly. Standard mayonnaise works, but add an extra pinch of sugar and a few drops of vinegar to come closer.

Variations and Swaps

• Add a boiled egg. Chop 1 hard-boiled egg and fold it in at step 6 for a richer, deli-style version common in Japanese convenience stores.
• Make it vegetarian. Skip the ham and add 1/3 cup thawed frozen peas or sweet corn for color and sweetness.
• Add apple for crunch. Some home versions fold in 1/4 of a crisp apple, diced small. Add it just before serving so it stays crunchy.
• Spicy edge. A teaspoon of karashi (Japanese mustard) instead of yellow mustard gives a sharper, nose-tingling heat. Start small.
• Pickled lift. A tablespoon of finely chopped pickled cucumber or takuan in place of half the fresh cucumber adds a fermented tang.

Storage and Make-Ahead Notes

Refrigerate in a sealed container for up to 3 days. The salad firms up as it sits, which is normal. If it seems dry on day two, fold in 1 to 2 teaspoons of mayonnaise and a pinch of salt, then taste again. Don't freeze it — the potatoes turn grainy and the mayo separates when thawed.

This is a good make-ahead side for a busy weeknight tray. Make it in the morning, chill it all day, and serve it cold next to a hot main. The flavors settle together in the fridge, and the cucumber stays crisp as long as it was salted and squeezed first.

What to Serve It With

Japanese potato salad likes company that is hot, crisp, or brothy. Serve it with fried chicken, tonkatsu, grilled fish, or a simple bowl of miso soup for a home-style set. In a bento box, pack it in a small cup so it doesn't press against hot rice. At a cookout, keep the bowl over ice and stir before serving — the top layer warms and softens faster than the center, and a quick fold brings the texture back together.

Japanese Potato Salad

Creamy, tangy Japanese potato salad, lightly mashed while hot and folded with Kewpie mayonnaise, cucumber, carrot, and ham, then chilled until the flavors settle.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 15 minutes mins

Total Time 35 minutes mins

Servings: 4 servings

Ingredients Method

Ingredients

  

For the potatoes

• 1 1/2 lb (680 g) waxy or all-purpose potatoes such as Yukon Gold peeled and cut into 1 1/2-inch chunks
• 1 tablespoon unseasoned rice vinegar
• 1 teaspoon granulated sugar
• 3/4 teaspoon fine sea salt plus more for the cooking water

For the mix-ins

• 1 small (about 4 oz / 115 g) Japanese or Persian cucumber thinly sliced into half-moons
• 1/4 teaspoon fine sea salt for salting the cucumber
• 1 small (about 2 oz / 55 g) carrot peeled and cut into thin quarter-moons
• 2 slices (about 2 oz / 55 g) deli ham cut into 1/2-inch squares
• 1/4 small yellow onion very thinly sliced
• 1/3 cup (80 ml) Kewpie mayonnaise plus more to taste
• 1/4 teaspoon freshly ground black pepper
• 1 teaspoon yellow mustard optional, for a sharper edge

Method

 

1. Salt the cucumber first. Put the cucumber slices in a small bowl, toss with 1/4 teaspoon salt, and set aside for 10 minutes. Squeeze the slices gently with your hands and pat dry before using.
2. Cook the carrot briefly. Bring a medium pot of salted water to a boil. Add the carrot and cook 1 to 2 minutes, until just tender at the edges but still firm in the center. Lift it out with a slotted spoon and spread it on a plate to cool. Keep the water boiling for the potatoes.
3. Boil the potatoes until just tender. Add the potato chunks to the same pot. Cook 10 to 12 minutes, until a knife slides in with slight resistance. Drain well and return them to the warm, empty pot for 1 minute to steam off surface water.
4. Season and mash while hot. While the potatoes are still steaming, sprinkle the vinegar, sugar, and 3/4 teaspoon salt over them. Mash about half of the potatoes with a potato masher or large fork, leaving the rest in soft chunks.
5. Cool before the mayo goes in. Spread the potatoes in a wide bowl and let them cool 10 minutes, until warm but no longer steaming.
6. Fold everything together. Add the squeezed cucumber, carrot, ham, onion, mayonnaise, black pepper, and mustard if using. Fold gently with a spatula so the chunks stay intact. Taste and add salt or another spoonful of mayo if it seems dry.
7. Chill, then taste again. Cover and refrigerate at least 30 minutes, or up to overnight. Taste again before serving and add a pinch of salt or a few drops of vinegar if it needs lift.