These Spicy Crab Onigiri, or Japanese rice balls, are the perfect snack for any time of the year. It’s fun to make and so tasty! Includes instructions with and without a mold.
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Onigiri
“Onigiri” are Japanese rice balls, a quick and easy meal that requires minimum fuss. They’re often included as part of a bento lunch box, but are also a great snack option.
Otherwise known as “omusubi”, these delicious rice balls are stuffed with a myriad of different fillings and seasonings, and usually wrapped in seaweed sheets called nori. They’re normally shaped as triangles, but you can also opt to roll them into simple balls!
The best thing about onigiri is that you can munch on it at any time of the day! And in Japan, you can easily find these savory morsels in convenience stores or even cafes.
spicy crab onigiri
The spicy crab filling for this onigiri is actually pretty simple to make! Imitation crab is mixed with a creamy, savory sauce made from Japanese mayo, Sriracha, and green onions.
I’ve also included two different methods for you to roll the rice balls, that is by using the mold, or without the mold.
Related: For another option, try out these Spicy Tuna Onigiri (Japanese Rice Balls)!

Ingredients You’ll Need
(For full ingredient measurements, please proceed to the recipe card below.)
- Freshly cooked Japanese short grain rice: I recommend using freshly cooked warm Japanese short grain rice as it sticks together better, making it easier for you to shape the onigiri. Sushi rice has shorter grain, which is why it sticks together effortlessly while still being fluffy. You can try to substitute with other short grain rice that’s available.
- Imitation crab
- Japanese mayo
- Sriracha
- Green onions
- Roasted seaweed (optional)
- Furikake (optional)
how to make spicy crab onigiri (japanese rice balls)
Spicy Imitation Crab
- Mince the thawed imitation crab finely and dice the green onions.
- Mix the crab, Japanese mayo, Sriracha and green onion in a bowl. Let it chill uncovered in the fridge for at least 15 minutes.
Rice Balls (without mold)
- Wet your hands. Take a pinch of salt and rub it all over your hands.
- Spread a layer of rice on your hands and create a small well in the middle, add about 1/2 tbsp of the filling and add another thin layer of rice on top. With just enough pressure, cover the filling with the rice. Keep putting gentle but firm pressure until it forms a triangle or the shape that you desire.
- Add a layer of roasted seaweed at the bottom center if eating it immediately. Optional: Dip the top sides of the onigiri in the furikake. Serve and enjoy!

Rice Balls (with mold)
- Cover the bottom half of the mold with rice and then make a well in the middle for the filling by pressing down the middle with clean fingers.
- Add the filling in the well and press down gently. Add more rice on top and flatten it out. Add the top part of the mold and press down to form the onigiri. Remove the top part of the mold and flip it over your palm. Push the mold from below and tap gently to release the onigiri. Enjoy!
- Add a layer of roasted seaweed at the bottom center if eating it immediately. Optional: Dip the top sides of the onigiri in the furikake. Serve and enjoy!

notes for spicy crab onigiri (japanese rice balls)
- Warm Japanese short grain rice is the best for the onigiri.
- Wet your hands before shaping the onigiri to prevent the rice from sticking to your hands.
- A pinch of salt is spread all over your hands to make the onigiri last longer and to flavor the rice.
- Use gentle but firm pressure to shape the onigiri so it doesn’t fall apart.
- You can use any filling for this as well, be creative! Use less mayo if you don’t want it to be too creamy. Adjust accordingly. (Option: Spicy Tuna Onigiri (Japanese Rice Balls))
- If not eating immediately, it’s best to not add roasted seaweed as it will get soggy.
More Japanese Recipes
- Japanese Garlic Fried Rice (15 Minutes)
- Karaage Don (Japanese Fried Chicken Rice Bowl) | Without Mirin or Sake
- Japanese Chicken Katsu Curry
- Ebi Fry (Fried Shrimp Japanese-style)
- Gyudon (Japanese Beef Rice Bowl) – No Mirin or Sake
- Japanese Potato Cheese Croquette (Korokke)
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Spicy Crab Onigiri (Japanese Rice Balls)
Equipment
- 1 onigiri mold optional
Ingredients
- 3 cups freshly cooked Japanese short grain rice
- 6 sticks imitation crab finely minced
- 4 tbsp Japanese mayo
- 4 tbsp Sriracha
- 1 tbsp green onions finely minced
- roasted seaweed optional
- furikake optional
Instructions
Spicy Imitation Crab
- Mince the thawed imitation crab finely and dice the green onions.
- Mix the crab, Japanese mayo, Sriracha and green onion in a bowl. Let it chill uncovered in the fridge for at least 15 minutes.
Rice Balls (without mold)
- Wet your hands. Take a pinch of salt and rub it all over your hands.
- Spread a layer of rice on your hands and create a small well in the middle, add about 1/2 tbsp of the filling and add another thin layer of rice on top. With just enough pressure, cover the filling with the rice. Keep putting gentle but firm pressure until it forms a triangle or the shape that you desire.
- Add a layer of roasted seaweed at the bottom center if eating it immediately. Optional: Dip the top sides of the onigiri in the furikake. Serve and enjoy!
Rice Balls (with mold)
- Cover the bottom half of the mold with rice and then make a well in the middle for the filling by pressing down the middle with clean fingers.
- Add the filling in the well and press down gently. Add more rice on top and flatten it out. Add the top part of the mold and press down to form the onigiri. Remove the top part of the mold and flip it over your palm. Push the mold from below and tap gently to release the onigiri. Enjoy!
- Add a layer of roasted seaweed at the bottom center if eating it immediately. Optional: Dip the top sides of the onigiri in the furikake. Serve and enjoy!
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