Onigiri: the adorable, portable, and undeniably delicious Japanese rice ball that’s been fueling busy people for centuries. Whether you grab one from a konbini (Japanese convenience store) or make them fresh at home, the magic of onigiri lies in the onigiri fillings. But with so many options, where do you start?
Fear not, fellow food lover! We’re diving into six of the most popular onigiri fillings straight from Japan.
Want to make your own? Check out our Tuna Mayo Onigiri Recipe!

Tuna Mayo Onigiri Filling: A Japanese Favorite
The undisputed queen of onigiri fillings. Creamy, savory, and ridiculously satisfying, tuna mayo is a favorite for a reason. It’s basically Japan’s answer to a tuna salad sandwich—only way cuter and way more delicious.
Why it’s great: The umami from canned tuna mixed with Japanese mayo creates a perfectly balanced, creamy bite every time.
Want to make it? Here’s our Tuna Mayo Onigiri Recipe!
Umeboshi (梅干し) – Pickled Plum
If you love bold, tangy flavors, umeboshi is your new best friend. These Japanese pickled plums pack a sour punch and are said to have stomach-soothing benefits.
Why it’s great: The tartness of umeboshi contrasts beautifully with the mild rice, making it a refreshing and addictive choice.
Salmon (鮭) – Salted or Grilled Salmon Onigiri fillings
Simple but oh-so-effective. Flaky, salty salmon is a staple in onigiri culture, and for good reason—it’s delicious, nutritious, and pairs beautifully with rice.
Why it’s great: The natural umami and slight saltiness of salmon create a comforting and satisfying bite.
Okaka (おかか) – Bonito Flakes & Soy Sauce
This filling is made by mixing katsuobushi (dried bonito flakes) with a splash of soy sauce. The result? A smoky, umami-packed onigiri that’s deeply satisfying.
Why it’s great: The flakes absorb the soy sauce, creating a punchy, salty, and slightly sweet flavor explosion in your mouth.
Kombu (昆布) – Simmered Kelp Onigiri fillings
Kombu is seaweed that’s been slow-cooked in soy sauce and mirin, resulting in a sweet and savory filling. It’s a favorite among traditionalists and those who love deep umami flavors.
Why it’s great: The soft, slightly chewy texture of kombu adds a unique bite, while the umami-rich flavor makes it a standout.
Tarako (たらこ) – Salted Cod Roe Onigiri Fillings
For those who enjoy a bit of a seafood kick, tarako (salted cod roe) is a briny, slightly spicy filling that adds a bold flavor to your onigiri.
Why it’s great: The delicate yet intense oceanic taste makes it a favorite among adventurous eaters.

FAQ: Everything You Need to Know About Onigiri Fillings
Tuna mayo and salted salmon are two of the most popular onigiri fillings, loved for their rich flavors and satisfying textures.
Absolutely! Some people love combining tuna mayo with avocado or adding a hint of umeboshi to balance out richer fillings.
Wrap your onigiri in plastic wrap or store them in an airtight container. If using nori (seaweed), keep it separate until you’re ready to eat for maximum crispiness.
Yes! Onigiri can be made a few hours ahead. Just keep them at room temperature or refrigerate them if storing for longer periods.
Japanese short-grain rice (sushi rice) is the best choice. It’s sticky enough to hold its shape without falling apart.