Your Phone Is Protected in a Waterproof Case. But What About Your Wallet and Keys? The Bestselling Pouch Loved by Those Wanting to Escape 'Bag Watching' at Beaches and Pools

The 'Mizuasobi' series of waterproof pouches from BELLEMOND (Bellemond), a brand operated by Fun Standard Co., Ltd. (a subsidiary of RKB Mainichi Holdings Corporation; headquarters: Ōnojō City, Fukuoka Prefecture; CEO: Ryosuke Oya, Hiroki Sasamori), has achieved bestseller status on Amazon's 'Waterproof Cases & Diving Bags' ranking with its large-capacity model, 'Mizuasobi Plus' (as of July 3, 2026).

'Mizuasobi Plus' is a waterproof pouch equipped with IP68 waterproof performance and a 4-layer structure combining triple zippers and Velcro, capable of protecting smartphones, wallets, keys, and cash from water damage all at once.

It has gained popularity as a solution for a common summer dilemma: someone always has to stay onshore as the 'bag watcher' while others swim, and valuable items like phones, wallets, and car keys are left unattended. Many people have expressed anxiety over their valuables, preventing them from fully enjoying water activities. Addressing this pain point, 'Mizuasobi Plus' secured the #1 spot on Amazon's bestseller ranking for waterproof cases and diving bags. The series has even claimed both the #1 and #2 spots on the same ranking. With 4-way carry options—shoulder, waist, body, and hand—it allows users to enter the water while keeping their belongings securely attached, enabling the whole family to play without worrying about their items.

※The video shows the slim-type 'Mizuasobi,' not the 'Mizuasobi Plus'.

Available on Amazon and Rakuten Market

Amazon Official Store

Rakuten Market Official Store

Solving the 'Bag Watching' Problem at Beaches and Pools

Enjoy water play with your whole family without worrying about your belongings. The 'Mizuasobi Plus' waterproof pouch lets you keep valuables with you at beaches, rivers, SUP spots, and spa resorts.

When families or friends go to the water, someone always has to stay behind to watch the bags.

At beaches without lockers, it's a constant worry where to leave phones, wallets, and car keys. Many people feel anxious about their valuables, unable to fully enjoy their time in the water.

Reasons for Ranking Success

Gusseted 'Mizuasobi Plus'

Slim 'Mizuasobi'

'Mizuasobi Plus' claimed the #1 spot on Amazon's bestseller ranking for waterproof cases and diving bags. The series has achieved both #1 and #2 positions. Users praised its ability to carry all valuables together—answering feedback such as 'I had a waterproof phone case, but nothing that could fit my keys and cash too.'

※Bestseller on Amazon's 'Waterproof Cases & Diving Bags' ranking as of July 3, 2026

Development Background

'Mizuasobi Plus' — Protecting more than just smartphones: long wallets, keys, sunscreen, and even water bottles

While waterproof phone cases exist, there were no practical tools to protect other essentials like wallets, keys, and sunscreen. The 'Mizuasobi' series was created to solve this frustration at water sites. We developed it with the vision that families could jump into the water together, free from worries about their belongings, and enjoy those moments together.

3 Key Features

Top-tier IP68 waterproof rating: No water ingress even at 1.5 meters depth for 30 minutes. Also blocks sand and dust, ensuring peace of mind at the beach.

High waterproof performance with IP68 and 4-layer structure: Triple zippers and Velcro ensure contents stay dry even when fully submerged.

Spacious gusseted design: Stores smartphones, wallets, keys, and cash, as well as sunscreen and water bottles.

4-way carry convenience: Wear it as a shoulder, waist, body, or hand pouch. Enter the water with your valuables securely attached.

User Testimonials

'I used to leave the water quickly because I was worried about my stuff on the sand, but this time I could play with peace of mind.'

'Great when going to rivers or beaches with kids.'

'I swam with it over my shoulder and the inside stayed completely dry.'

—Feedback highlights the sense of security it provides at water sites.

Available on Amazon and Rakuten Market

Amazon Official Store

Rakuten Market Official Store

About BELLEMOND

BELLEMOND is a lifestyle brand offering products that customers feel 'good to use,' focusing on iPad films and smartphone accessories. From 2025 onward, the brand aims to connect with one million users by expanding into products for more daily-life scenarios, such as fans, sun umbrellas, and aroma diffusers.

Amazon: https://www.amazon.co.jp/stores/page/378CB368-6A7C-4B49-A2F6-92511350DFE6?channel=PRT-brand

Rakuten Market: https://www.rakuten.ne.jp/gold/mobile123/

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