Japanese Hot Spring Eggs (Onsen Tamago)

Name: Japanese Hot Spring Eggs (Onsen Tamago)
Prep time: 5 min
Cook time: 22 min
Total time: 27 min
Cuisine: Japan
Ingredients: 4 large eggs; 8 cups (1.9 L) water, or enough to cover the eggs by 1 inch; 2 cups (480 ml) ice water, for stopping the cooking; 1/2 cup (120 ml) dashi (Japanese stock, preferably kombu and bonito; or use kombu dashi); 2 tbsp (30 ml) soy sauce; 2 tbsp (30 ml) mirin; 1 tsp (4 g) sugar; 1 scallion, thinly sliced, for garnish

温泉卵 Onsen tamagoSay it: OHN-sen tah-MAH-goh

By the Passport Plate editors. Published November 7, 2026.

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Onsen tamago are Japanese hot-spring eggs, gently cooked in their shells in water around 70°C until the white is barely set and the yolk turns soft and custard-like. Despite the name, they are easy to make at home with a thermometer and a pot. They are eaten for breakfast or as a small appetizer, often chilled and served in a warm dashi-soy broth with scallions. The appeal is textural: silky, trembling egg against a savory, slightly sweet broth.

Japanese Hot Spring Eggs (Onsen Tamago)

温泉卵, Onsen tamago

Pronounced OHN-sen tah-MAH-goh

Serves: 4
Prep: 5 min
Cook: 22 min
Total: 27 min
Level: Easy

Dairy-free

Also nut-free.

Allergens: contains egg, soy, fish. Check labels on packaged ingredients.

Ingredients

4 servings

Eggs and cooking bath

4 large eggs
8 cups (1.9 L)1.9 L (8 cups) water, or enough to cover the eggs by 1 inch
2 cups (480 ml)480 ml (2 cups) ice water, for stopping the cooking

Dashi-soy broth

1/2 cup (120 ml)120 ml (1/2 cup) dashi (Japanese stock, preferably kombu and bonito; or use kombu dashi)
2 tbsp (30 ml)30 ml (2 tbsp) soy sauce
2 tbsp (30 ml)30 ml (2 tbsp) mirin
1 tsp (4 g)4 g (1 tsp) sugar
1 scallion, thinly sliced, for garnish

Method

Fill a large pot with the 8 cups (1.9 L) water and heat over medium until it reaches 158°F (70°C). Keep a thermometer in the water and adjust the heat so it stays between 155°F and 165°F (68–74°C).
Gently lower the eggs into the water with a slotted spoon. Cover the pot and cook for 22 minutes, checking the temperature every few minutes and adjusting the heat as needed to keep it steady.
Meanwhile, make the broth. combine the dashi, soy sauce, mirin, and sugar in a small saucepan. Warm over low heat, stirring until the sugar dissolves, about 2 minutes; do not let it boil, then set aside.
When the eggs are done, transfer them with a slotted spoon to the ice water and chill for 2 minutes to stop the cooking.
Crack each egg into a small bowl or cup; the white should be barely set and the yolk soft and custard-like.
Spoon the warm dashi-soy broth around the eggs, garnish with the scallions, and serve immediately.

Regional variants

Serve the eggs over hot rice or udon, or add a little grated ginger or yuzu zest to the broth. Some cooks use mentsuyu diluted with dashi instead of the soy-mirin mixture.

Cook's notes

Use a kitchen thermometer; onsen tamago depends on a steady low temperature more than exact timing.
Start with eggs straight from the refrigerator and lower them gently to avoid cracking.
Kombu dashi makes a vegetarian version; regular dashi contains bonito flakes.

Serve with

Steamed rice, udon, or a Japanese breakfast spread with pickles and miso soup.

Make ahead and storage

The broth can be made up to 3 days ahead and refrigerated; cook the eggs just before serving.

Japanese Hot Spring Eggs (Onsen Tamago)