Overview of Mobile Network Operators in Japan and Guide to Choosing the Right SIM

When first arriving in Japan to study, work, or settle down, one of the most important first tasks you need to handle is registering for mobile service. However, the telecommunications market in Japan is extremely diverse with various network tiers, ranging from giant telecom conglomerates and sub-brands to virtual network providers. Without thorough research, users can easily run into troubles with payment procedures, contract commitments, or monthly costs that exceed their actual needs. This article will provide the most comprehensive, accurate, and detailed overview of mobile carriers in Japan today, helping you choose the most optimal communication solution.

1. The Big Four Carriers (MNO - Mobile Network Operator)

MNOs are entities that own all base station infrastructure and their own radio frequency spectrum in Japan. The four telecom giants holding the main market share today include NTT Docomo, au (KDDI), SoftBank, and Rakuten Mobile.

NTT Docomo

NTT Docomo is the longest-standing carrier with the widest coverage in Japan, particularly strong in remote areas, deep rural regions, and islands. Docomo's signature unlimited data plan is "ドコモMAX" with a listed price of 8,448 yen/month. When customers apply all accompanying promotion programs, such as bundling home internet lines, paying via an affiliated credit card, or family member discounts, the cost can drop to around 5,148 yen/month.

au (KDDI)

au belongs to KDDI group, competing head-to-head with Docomo in terms of service quality and coverage area. au's unlimited data plan has a base price of 8,008 yen/month. Similar to Docomo, if users meet all conditions for combining fixed-line services and household discounts, the actual monthly price drops to around 5,478 yen/month.

SoftBank

SoftBank is famous for creative media campaigns and a rich entertainment ecosystem. SoftBank's unlimited data plan "テイガク無制限" is listed at 8,008 yen/month. After applying all eligible discounts, the monthly usage cost drops to about 5,148 yen/month.

Rakuten Mobile

Rakuten Mobile is the fourth carrier to join the MNO market, but it makes a big difference thanks to its flexible tiered pricing policy. Instead of charging a fixed rate, Rakuten charges based on the actual data used in a month: under 3GB costs 1,078 yen/month; from 3GB to 20GB costs 2,178 yen/month; and when using over 20GB, the fee caps at a maximum of 3,278 yen/month for unlimited data.

2. Sub-brands

To retain customers who want to save costs while still prioritizing direct use of MNO infrastructure, major carriers have launched sub-brands. These plans streamline direct customer care services to offer more attractive pricing.

• ahamo (Docomo): Offers a 2,970 yen/month plan for 30GB data, including 5 minutes of free calls per call. For higher usage needs, users can choose an expanded 110GB option for 4,950 yen/month.
• povo 2.0 (au): Applies a 0-yen base tariff model, where users purchase additional data add-ons based on their needs. The price for 30GB of data is around 2,780 yen.
• LINEMO (SoftBank): Has two main plans: a 3GB plan for 990 yen/month and a 30GB plan with 5 minutes of free calls for 2,970 yen/month.
• UQ mobile (au): Offers a 5GB plan for 2,948 yen/month and a 35GB plan with 10 minutes of free calls for 3,828 yen/month.
• Y!mobile (SoftBank): Offers a 5GB plan for 3,278 yen/month.

Important note: Most sub-brands require users to register entirely online and almost mandatory payment using a credit card issued in Japan. This creates a significant barrier for newcomers who haven't had time to open a local bank account or obtain a Japanese credit card.

3. Virtual Networks (MVNO - Mobile Virtual Network Operator)

MVNOs are entities that do not own their own broadcast tower infrastructure but lease lines from major MNOs to operate telecommunications services. By optimizing operational and infrastructure costs, the general market rate for MVNOs for 20GB of data ranges from approximately 1,900 to 2,200 yen/month, significantly cheaper than main carrier plans.

Advantages of MVNOs

Very economical monthly rates, flexible registration procedures, and affordable for students, trainees, and foreign workers.

Disadvantages to consider honestly

Despite offering high economic value, MVNOs also have limitations that users should know before choosing. Due to sharing leased bandwidth, MVNO internet speeds may slow down during peak hours, such as 12:00 PM (lunchtime) and 8:00 PM–10:00 PM (evening home entertainment hours). Additionally, MVNO carriers usually have very few or no physical storefronts for direct support. Furthermore, data-only plans from MVNO networks do not include a traditional phone number for voice calls.

4. Comparison Table of Mobile Network Tiers in Japan

Below is a summary table of main features to help you clearly understand the differences among the three mobile service groups in Japan:

5. Which Solution Should New Vietnamese Arrivals Choose?

For Vietnamese who have newly arrived in Japan to live, study, or work, choosing a mobile network heavily depends on document availability and practical financial conditions:

1. If you just arrived and don't have a Japanese credit card yet: Choosing major MNO carriers or sub-brands will present a major barrier because procedures require a domestic Japanese credit card or a long-standing Japanese bank account. In this case, registering with an MVNO carrier that supports COD (Cash on Delivery) or convenience store (combini) payment is the most convenient solution.
2. If your primary need is internet access, web browsing, and calling via apps: Registering for a traditional calling plan adds unnecessary fixed monthly expenses. You can use a Data-only SIM plan to access the internet and easily communicate via Zalo, LINE, or Messenger while saving costs.
3. If you are concerned about language barriers: Finding providers that support Vietnamese will help you easily communicate, answer questions, and receive fast technical support during usage.

6. Introduction to Solutions from HD TELECOM

HD TELECOM is an MVNO carrier under the legal entity 株式会社ベトナム物産, operating under telecom business license number A-06-22505. The office headquarters is located at 〒169-0073 東京都新宿区百人町1-16-18 センチュリービル2F, right near Shin-Okubo station for convenient access. Customers can contact the hotline at 03-6789-8553 or email support@hdtelecom.jp for assistance.

HD TELECOM provides SIM services running on the network infrastructure of all 4 major carriers in Japan: Docomo, au, SoftBank, and Rakuten. However, customers should note that the official website currently lists ready-made plans using SoftBank and Rakuten underlying networks. For plans running on Docomo and au underlying infrastructure, please contact customer support directly for a detailed quote.

Starting service prices listed on HD TELECOM's website include:

• Monthly Data SIM: Starting at just 1,800 yen/month.
• Monthly eSIM: Starting at just 2,500 yen/month.
• Monthly Pocket WiFi: Starting at just 4,500 yen/month.
• 12-Month Prepaid SIM: Starting at just 8,000 yen.

Key highlights of choosing HD TELECOM services:

• Easy payment: Supports COD (cash on delivery to your door), bank transfer, and payment via convenience stores (combini). You can easily register and use services without needing a Japanese credit card.
• Professional Vietnamese support: A team of Vietnamese consultants provides dedicated support from plan selection and configuration setup to resolving arising questions.
• No long-term contract commitments: Customers are not tied down by multi-year contracts or unreasonable cancellation penalty fees.
• Plan format: Current service packages are DATA-ONLY plans (do not support traditional voice call services via phone number). Nevertheless, users can freely make voice and video calls through popular apps such as Zalo, LINE, Messenger, or Telegram.

7. Frequently Asked Questions (FAQ)

Will MVNO networks like HD TELECOM experience sudden service disconnections?

No. MVNO services operate on official infrastructure leased from major MNOs like SoftBank, Rakuten, Docomo, and au, so coverage and connection stability are fully guaranteed according to Japanese telecom standards.

Why can't HD TELECOM SIM plans make regular phone calls?

HD TELECOM's current plans are dedicated Data-only packages to optimize monthly costs for users. Customers do not need to pay extra fixed phone number subscription fees while still staying connected seamlessly via internet communication software like Zalo, Messenger, and LINE.

Can I register for an HD TELECOM SIM without a Japanese credit card?

Absolutely. HD TELECOM supports COD (paying cash to the delivery staff upon receiving the SIM), bank transfer, or payment at combini, making it ideal for Vietnamese newly arrived in Japan.

How are MVNO network speeds during peak hours?

Because leased infrastructure is used, during peak hours such as 12:00 PM or 8:00 PM–10:00 PM, internet speeds on MVNO networks may be slightly slower than usual. However, basic operations like messaging, browsing the web, or watching regular videos still meet daily needs well.

8. Conclusion

Understanding the overall landscape of mobile carriers in Japan will help you make a smart choice that fits your financial situation and personal document status. If you are looking for a convenient mobile internet solution without requiring a Japanese credit card, long-term contract commitments, and with full support in Vietnamese, contact HD TELECOM right away to get advised on the best plan for you.

*Note: Prices and plan details mentioned in this article are updated as of August 2026 and may change over time. Please check official information on the website or contact HD TELECOM directly for the most accurate update.