There’s nothing crisper than a McDonald’s Sprite—at least, not until now. MTN WTR’s newest drop, EXTRA STRONG Sparkling Water, takes Japan’s latest craze for ultra-carbonated beverages and brings it stateside this fall.
This isn’t your average seltzer. It’s made from alkaline spring water filtered through volcanic rock beneath Mount Fuji, delivering a hit of fizz that feels like a wake-up call in a can. Americans are about to discover how addictive and refreshing carbonation on overdrive can feel.
Meet the Sparkling Water That Doesn’t Hold Back
Japan has taken carbonation to the extreme, and MTN WTR is betting Americans are ready for water with an edge. The brand sources naturally alkaline spring water from Mount Fuji, where it filters for nearly half a century through protected volcanic terrain in Japan’s most popular national park. This produces a naturally soft water with a subtle taste, an alkaline pH of 8.6, and a silky mouthfeel.
Now, MTN WTR is turning up the bubbles. EXTRA STRONG packs 4.0-4.5 volumes of CO₂ per can—nearly double the fizz (2.0-2.5 volumes) of its classic sparkling variety. Japanese drinkers love this style for its palate-cleansing bite and lively mouthfeel, and now U.S. consumers can finally try it too.
“We saw an opportunity to give people both a bigger sip and the freedom to choose their sparkle,” says Masa Kinemuchi, founder and CEO of MTN WTR. “No other water brand in the U.S. offers two distinct carbonation levels, so we decided to lead the way.”
The brand has been selling its Japanese sparkling water in the U.S. since 2022, and this fall, they’re expanding with new 500 mL (16.9-ounce) cans, an upgrade from their 16-ounce format, still priced around $1.99. The single cans hit stores in late August 2025, with 24-packs launching at distributors and Amazon in late September. You’ll also find them in hundreds of stores and restaurants, including Erewhon, H Mart, 99 Ranch, and Amazon.
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Carbonation That Elevates Everything It Touches
On its own, EXTRA STRONG is a refreshing, almost electric experience, instantly waking up your palate after the first sip. In Japan, bartenders use ultra-carbonated water to keep whisky highballs crisp from first pour to last. Those vigorous bubbles add an energizing jolt that makes cocktails taste sharper, brighter, and more refreshing. They’re just as good in a gin and tonic, a Paloma or a low-ABV spritz.
Outside the bar, those bubbles act as a palate cleanser, cutting through spice or rich barbecue so every bite hits fresh. They’re just as effective next to an espresso, clearing your palate between shots. And if you’re skipping booze, the crackling fizz makes mocktails and aperitifs feel like a special occasion. Just remember: serve it ice-cold, use big cubes, and don’t stir too hard if you want to hold onto that hard-hitting carbonation.
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