The "Awaji Island New Onion Burger - Japanese Soy Sauce Style" is returning to MOS Burger stores in the Kansai, Chugoku, and Shikoku regions from May 7, 2026 (Thursday) through mid-May. Now in its 11th year, this spring seasonal item uses fresh new onions cultivated by contracted farms on Awaji Island and continues to be a popular draw — with many stores selling out ahead of the end of the sales period each year.
The burger first appeared in the Chugoku and Shikoku regions in 2016 and has since become an annual spring tradition, expanding to Kansai stores as well. It spotlights the fresh "new onion" — a particularly juicy and tender variety of Awaji Island's signature high-sugar onions — suited for raw consumption, and uses it generously.
Awaji Island New Onion Burger - Japanese Soy Sauce Style (¥510)
Green leaf and a juicy patty are topped with thick rings of fresh new onion, sliced at each store, then finished with a "tamanegiburger sauce" and bonito flakes. The sauce is a Japanese-style blend of soy sauce, concentrated apple juice, and shio-koji powder — savory and mellow with a refreshing edge. The bonito flakes used are "kare-bushi," a variety produced over three to four months using katsuobushi mold (a type of koji mold), lending the burger a more complex, rounded flavor. The result is a light yet satisfying burger that lets the seasonal onion shine.
A cheese option is available for an additional ¥40, bringing the total to ¥550.
Product Overview
- Product name & price: Awaji Island New Onion Burger - Japanese Soy Sauce Style — ¥510 / with cheese — ¥550 (all prices tax included)
- Sales period: May 7, 2026 (Thursday) through mid-May 2026
- Available locations: 283 MOS Burger stores in the Kansai, Chugoku, and Shikoku regions (some stores excluded)
