Onigiri, or Japanese rice balls wrapped in seaweed, are a traditional dish that represents the heart of Japanese food culture.
Following our previous introduction of Salmon onigiri, today we’re featuring Tuna Mayo, one of the most popular fillings—even among people outside of Japan.
The savory flavor of tuna and the richness of mayonnaise, enhanced with a touch of soy sauce, create a perfect balance in this classic rice ball.
Give this beloved Japanese comfort food a try and enjoy a taste of what many consider the “soul of Japan”!
Table of Contents
What is Onigiri?
It’s mentioned on the Salmon onigiri (Japanese rice balls) page.
The Story Behind This Recipe
Tuna mayo is one of the most popular onigiri fillings in Japan, consistently ranking near the top in flavor polls.
Today, it’s considered a classic choice, but compared to long-standing fillings like pickled plum or salted salmon, which have been eaten for centuries, tuna mayo is a relatively recent addition.
It’s said that tuna mayo onigiri first appeared in 1983, when the Japanese convenience store chain 7-Eleven introduced it as a new product.
The idea reportedly came from a product developer who was inspired by his child putting mayonnaise on rice at home.
Nowadays, onigiri are a staple in Japanese convenience stores, but back then, they weren’t considered strong sellers—many believed people wouldn’t buy something so easy to make at home.
That perception changed with the growing popularity of tuna mayo onigiri, along with the introduction of a new packaging style that keeps the seaweed separate until just before eating to maintain its crispness.
These innovations helped turn onigiri into a best-selling item in Japanese convenience stores.
In recent years, tuna mayo onigiri has also been gaining popularity overseas, thanks to the global rise of Japanese cuisine and the dish’s simple, comforting flavor.
It’s often one of the easiest onigiri fillings to recreate at home, making it a favorite among those trying Japanese food for the first time.
Ingredients (Serves 2)
- Cooked rice – 1 bowl (about 7 oz / 200 g, freshly cooked)
- Canned tuna – 1 can (about 2.5 oz / 70 g)
- Mayonnaise – 1 tbsp / 0.53 oz / 15 g
- Soy sauce – 1 tsp / 0.17 oz / 5 g
- Sea salt – to taste (Using mineral-rich sea salt adds mildness and depth of flavor)
- Toasted nori (seaweed) – ⅔ sheet (lightly toasted and cut into pieces)
Instructions
| 1 |
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Pat the tuna dry with a paper towel to remove excess moisture and oil, then mix it with mayonnaise and soy sauce. |
| 2 |
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Wet your hands with water, sprinkle with a pinch of salt, and place about 90 g (3.2 oz) of cooked rice in your palm. Add the tuna mayo mixture in the center. Tip Rice tends to stick to your hands, so keeping your hands wet is key! Here we introduce the traditional method of shaping by hand, but you can also use plastic wrap or food-safe gloves for a more hygienic approach. |
| 3 |
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Place a small amount of rice over the salmon to cover it lightly. |
| 4 |
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Gently cup the rice between both hands and shape it into a triangle by softly pressing and rotating your hands about four times while saying “O-mu-su-bi” (just like the rhythm of the word). Tip Use freshly cooked hot rice and shape it gently—if you squeeze it too tightly, the rice becomes mashed and sticky, making it harder to eat. By gently shaping and incorporating some air, the rice stays fluffy and holds its shape even after cooling. This results in a soft, tender onigiri that keeps its form yet falls apart pleasantly in your mouth. |
| 5 |
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Wrap the rice ball with a strip of toasted nori and optionally garnish the top with a little more tuna mayo. Tip Lightly toasting the nori brings out its rich aroma and crisp texture. You can enjoy it crisp by wrapping the nori just before eating, or wrap it in advance to let it soften and blend with the rice—the choice is yours! |
How to Shape Onigiri – Video
Top Spots in Japan We Recommend — 7-Eleven セブンイレブン
If you want to try tuna mayo onigiri, we recommend visiting 7-Eleven, which is known as the place that popularized it.
7-Eleven is the largest convenience store chain in Japan, with over 20,000 locations across the country, so you’ll have no trouble finding one wherever you go.
They offer a wide variety of onigiri, so feel free to try not only tuna mayo, but also any others that catch your eye.
Japanese convenience store food is known for its surprisingly high quality—affordable, delicious, and popular even among tourists.
At 7-Eleven, you’ll find onigiri with fillings like grilled salmon, pickled plum, kelp, spicy cod roe, and more, all beautifully arranged and easy to pick up.
The packaging is also unique: the seaweed is kept separate from the rice until you open it, so it stays crisp—one of many small but thoughtful touches that reflect Japan’s attention to detail.
Trying onigiri from a convenience store is a fun and memorable way to experience Japanese food culture during your trip.
7-Eleven セブンイレブン
Official Website