5 from 6 votes

Learn how to make a popular Japanese rice ball, Tuna Mayo Onigiri! With only five ingredients, you can have them ready in under ten minutes!

Looking for more onigiri recipes? Try my Okaka Onigiri, Salmon Onigiri, Egg Onigiri!

I’ll walk you through the ingredients and step-by-step instructions. I hope you enjoy it!

Why You Will Love This Recipe

This Tuna Mayo onigiri is the perfect lunchbox addition, breakfast, or a convenient snack!
Easy-to-follow steps and minimal ingredients make this recipe beginner-friendly.
This recipe also includes five delicious tuna mayo filling variations to enjoy more!

Onigiri (Japanese Rice Balls)

Onigiri is a Japanese food made of steamed rice filled with ingredients, formed into a triangle shape, and wrapped in seaweed. It’s perfect for a quick meal or snack, and the best part is you can easily customize it by choosing your favorite onigiri fillings.

Recipe Ingredients

You’ll need the following ingredients to make this Tuna Mayo Onigiri:

We use Japanese short-grain rice for making onigiri as it’s sticky and can hold the shape of triangular shape.
Nori seaweed is a type of seaweed that’s dried, crispy, and sold in sheets like the picture above. Get this full-size nori sheet (8.3”x 7.5” or 21 x 19 cm in general) at a grocery store. This size is too large for onigiri (perfect for a sushi roll, though), so we are going to divide it into 3.
You can use canned tuna in water or oil; both work perfectly. Before mixing with mayo, drain any excess liquid.
Japanese Mayonnaise adds authentic flavor. Popular brands like Kewpie or Ajinomoto are recommended, but regular mayonnaise can be used if unavailable.

How To Make Tuna Mayo Onigiri: STEP BY STEP

Here are some quick visual instructions! For the video and all the detailed ingredients and instructions, go to the printable recipe card below.

Step 1

Prepare tuna mayo filling by mixing canned tuna and mayonnaise.

Step 2

Put the rice in a small bowl and add the tuna mayo in the center.

Step 3

Form a triangle shape by pressing gently with both your hands.

Step 4

Wrap the triangular rice with nori.

Here you go! Eat right away if you like crispy nori seaweed. Or wait a few minutes for a softer texture, like in the picture!

A Different Way to Wrap Nori

How to wrap onigiri in nori seaweed step by step.

Here’s another method for wrapping the nori around the rice. With this technique, the rice is wrapped from both sides, so you don’t have to worry about the rice falling apart when eating.

Place the triangular-shaped rice in the center of the nori.
Fold the nori on both sides diagonally.
Fold the lower part of the nori toward the bottom of the rice.

I recommend placing the ingredients on top of Onigiri, like in the picture above. It’s easy to see what’s inside, but it also looks so cute!

Recipe Tips

Short-grain rice works best for onigiri as it is sticky and holds its shape well.
Use plastic wrap or onigiri molds to shape onigiri neatly, especially when the rice is too hot to handle.
When using nori seaweed, take a close look at the nori sheet. You’ll notice that one side is shiny, and the other side is slightly rough. Make sure to place the shiny side facing outward when wrapping the rice. This adds a visually appealing touch to your onigiri.

Variations of Tuna Onigiri

More variations for onigiri with tuna? I’ve got some suggestions for you! You can mix in ingredients like salty and spicy for a savory flavor!

Tuna Mayo and Wasabi: Add spicy Japanese horseradish, called wasabi, to the tuna mayo mixture for a spicy kick.
Tuna Mayo and Soy Sauce: Drizzle soy sauce over the tuna mayo filling for an extra savory flavor.
Tuna Mayo and Shio Kombu: Mix in seasoned kombu seaweed, known as shio kombu, to your rice for a tasty twist. (This is my favorite!)
Tuna Mayo and Kimchi: Mix in some spicy kimchi to add a Korean-inspired twist to your rice. If you’re looking for spicy tuna onigiri recipes, try this variation.
Tuna Mayo and Curry: Mix in some curry powder with your rice for a flavorful and aromatic onigiri.

five tuna mayo onigiri on a round plate.

There are endless combinations of onigiri with tuna! I hope you will enjoy exploring all the different flavors and find your favorite ones!

Storage

Onigiri is best when freshly made, but if you need to store them for later, follow these guidelines:

Wrap each onigiri tightly in plastic wrap to maintain their moisture.
At room temperature, onigiri can be stored for up to half a day.
In the fridge, they can be kept for a couple of days.
If you plan for longer storage, freeze them for up to one month. When freezing, avoid wrapping the nori sheet. Reheat in a microwave just before eating to prevent dryness; do not thaw at room temperature.

What To Serve With

Onigiri pairs well with many different dishes! I suggest serving with vegetable tempura, tofu seaweed salad, and daikon miso soup.

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Leave a Rating!

I hope you enjoy this Tuna Mayo Onigiri! If you try it, don’t forget to leave a rating to share your thoughts—I love hearing from you!