An Autumn Icon Returns for a Limited Time
BK Japan Co., Ltd. (headquarters: Chiyoda-ku, Tokyo; President & CEO Kazuhiro Nomura), operator of Burger King® in Japan, will bring back its beloved autumn classic, the Mushroom Whopper® line-up, from Friday, September 18, 2026, for a limited time. Three items are available: the Mushroom Whopper®, the Double Mushroom Whopper®, and the Mushroom Whopper® Jr. For many fans, this burger has become the signal that autumn has truly arrived.
Four Kinds of Mushrooms and a Premium Pepper Mayo Sauce
The star of the show is the generous use of four different mushrooms: two roasted mushroom varieties plus eringi (king oyster) and bunashimeji. Layered over a flame-grilled 100% beef patty, the mushrooms bring a deep, fragrant umami that plays beautifully against the smokiness of the grill. Fresh lettuce, tomato and onion are stacked on top, and the whole thing is finished with a creamy Premium Pepper Mayo Sauce that highlights the sweetness of onion with coarsely ground black pepper and a distinctive accent of toasted soy sauce.
Three Sizes to Choose From
- Mushroom Whopper®: One flame-grilled 100% beef patty — the balanced, classic version.
- Double Mushroom Whopper®: Two beef patties for a seriously satisfying, hearty option.
- Mushroom Whopper® Jr.: A handy smaller size, ideal for lighter appetites or pairing with sides.
Product Details and Pricing
- Mushroom Whopper®: 990 yen à la carte / 1,290 yen as a set
- Double Mushroom Whopper®: 1,440 yen à la carte / 1,740 yen as a set
- Mushroom Whopper® Jr.: 590 yen à la carte / 890 yen as a set
- On sale: From Friday, September 18, 2026, for a limited period
Sets include small French fries and a medium drink. All prices include tax.
Save Up to 23% with an App-Only Coupon
For two weeks only — Friday, September 18 through Thursday, October 1, 2026 — the official Burger King® app will distribute a special coupon. The Mushroom Whopper® Set drops from 1,290 yen to 990 yen, and the Double Mushroom Whopper® Set from 1,740 yen to 1,440 yen — a 300 yen discount, up to 23% off the regular price. The coupon is valid for both dine-in and takeout, with up to three sets per transaction. Downloading the app and registering as a member is required, and existing members are also eligible.
Things to Note
- At stores serving breakfast, sales begin after 10:30 a.m.
- Selling hours vary by store, and some locations do not carry these items.
- The coupon cannot be used for delivery or combined with other discounts.
- The Tokyo Racecourse, Kyoto Racecourse and Kansai International Airport Terminal 1 stores are excluded from both the product line-up and the campaign.
- Scan the QR code at self-service or staffed registers; at drive-thru, give the four-digit number and show the QR code at the payment window.
About Burger King®
Founded in 1954, the Burger King® brand operates more than 19,000 restaurants across over 120 countries and the United States, making it the world’s second-largest quick-service hamburger chain by restaurant count. In Japan, BK Japan Co., Ltd. oversees domestic marketing, restaurant operations, menu development and new store expansion. With fragrant mushrooms and flame-grilled beef in perfect harmony, this is a taste available only for a few short weeks — a delicious way to welcome autumn.