Overview

The PREMIUM CHARGE WIFI U20 is a contract-free mobile WiFi router sold directly by a Japanese manufacturer. You simply purchase the device, turn it on, and the service activates with an initial 365-day validity period that includes 100GB of data for use within Japan. No physical SIM contract and no credit card registration are required.
Weighing just 112g, the compact U20 supports up to 8 simultaneous connections, making it suitable for laptops, smartphones, game consoles, and even in-car use. There are no monthly fees whatsoever; when you run out of data, you simply purchase additional gigabytes as needed through the charge system.

Connectivity & Compatibility

The U20 uses a 4G cloud SIM that automatically connects to the optimal signal from Japan's four major carriers. This multi-carrier approach provides broad coverage across the country. Since no physical SIM card is required, the device works right out of the box.
Supported devices include laptops, cars, smartphones, game consoles, and smartwatches, all connecting via WiFi with up to 8 devices simultaneously. The device also supports international use in more than 150 countries and regions. For overseas travel, you purchase a separate plan for your destination country through the charge site, then simply turn on the device upon arrival.
Additional data charges can be paid with major credit cards including VISA, Master, JCB, Diners Club, American Express, and Discover, as well as debit cards such as Vプリカ, バンドルカード, and Kyash. Convenience store payment is also accepted.

Product Info

This is a device-purchase (buy-out) type mobile WiFi router sold under the PREMIUM CHARGE WIFI series with zero monthly fees. The pay-as-you-go model lets you add data anytime, 24/7, making it a flexible option for users who want to avoid fixed costs.
In terms of market positioning, the U20 sits in the entry-to-mid tier, aimed at users who prefer no contractual obligations or who have irregular usage patterns. The lightweight 112g body is easy to carry and works well in vehicles. The package includes the main unit, a USB Type-C cable, service guide, quick start guide, warranty card, and precautionary instructions. The technical conformity mark (技適マーク) is printed inside the device cover.

Best Use Cases

  • People who want to avoid contracts and credit card registration: purchase the device outright and start using it immediately with no monthly fees, keeping fixed costs at zero.
  • Users with irregular data needs: top up gigabytes only when necessary, so months with light usage cost nothing extra.
  • Travelers who need temporary connectivity abroad: works in over 150 countries and regions, with simple activation by turning on the device at the destination. Not necessary for those who only use it domestically.

Product Disclosure (Amazon)

  • Manufacturer: PREMIUM CHARGE WIFI
  • Seller: ONYANKOPON
  • Fulfilled by: Amazon
  • ASIN: B0DKH879YP
  • Note: This article covers a manufacturer-made product based on Amazon listing details.