How to Get and Activate au by KDDI SIM Cards and eSIM: Guide for Tourists

Daisy Rodriguez

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Latest update: September 2024

KDDI is one of the major mobile operators in Japan, providing high-speed 4G LTE coverage across most of the country. As a tourist visiting Japan, getting an au by KDDI SIM card or Japan eSIM can help you stay connected with easy data, calls, and texting while exploring Japan.

In this guide, we’ll cover everything you need to know about using au by KDDI SIM card and eSIM in Japan, including coverage and speeds, best connectivity options, where to buy, activation, top-up, and more.

I. Overview about au by KDDI – What you need to know

KDDI is the official name of the corporation, while au is the brand name for its mobile phone and internet services. Some quick things to know about KDDI’s mobile brand au:

• au is a Japanese mobile phone operator, or au by KDDI, a brand marketed by KDDI in the main islands of Japan and by Okinawa Cellular in Okinawa for their mobile cellular services. It is the second-largest wireless carrier in Japan, with over 60 million subscribers.
• au was founded in 1987 as DDI Cellular and was the first to launch a digital cellular network in Japan. The company adopted the name au in 2000.
• au is a subsidiary of KDDI, a Japanese telecommunications conglomerate. KDDI is also the parent company of Okinawa Cellular.
• au offers a wide range of mobile phone plans, including data, voice, and messaging plans. The company also offers a variety of other services, such as home broadband, television, and financial services.
• au is known for its innovative marketing campaigns, which often feature popular Japanese celebrities. The company has also been a pioneer in the development of new mobile technologies, such as 4G and 5G.

So in summary, KDDI au gives you fast, reliable connectivity across almost all of Japan – perfect for tourists exploring the country.

II. KDDI Coverage in Japan

Based on Opensignal’s October 2023 Mobile Network Experience Report for Japan, au’s coverage performance presents a mixed picture. While not the outright winner in any major category, it exhibits strengths and weaknesses worth mentioning:

• Third Place in Coverage Experience: With a score of 7.8 on a 10-point scale, AU lags behind NTT Docomo (9.1) and Rakuten Mobile (7.9) in the overall coverage department.
• Second Place in Availability: AU users spend 99.6% of their time connected to their network, only placing it behind NTT Docomo (99.7%).
• Joint Winner in 5G Availability: AU users spend 9.9% of their time connected to 5G, ranking first among four operators.

Overall, AU provides a good 5G coverage experience in Japan, with a strong signal availability in most areas.

III. KDDI speed in Japan

Based on Opensignal’s October 2023 Report for Japan, au’s speed shows both strengths and areas for improvement:

• Overall Download Speed: Tied with NTT Docomo for 2nd place with a score of 44.7 Mbps, which is respectable but not the leader.
• Overall Upload Speed: 3rd place with a score of 7.7 Mbps, falling behind both SoftBank and Rakuten Mobile.
• 5G Download Speed: Joint champion with Rakuten Mobile, boasting a blazing-fast 177.4 Mbps, demonstrating strong performance in the new generation network.
• 5G Upload Speed: 3rd place with a score of 14.9 Mbps, falling behind the leader Rakuten Mobile and SoftBank but still offering a significant improvement over 4G upload speeds.
• Video Experience: AU ranked 2nd with a score of 69.7 points, indicating a generally good experience for streaming video but lagging behind SoftBank.
• Consistent Quality: au scores 81.2%, tying with NTT Docomo for 3rd place. This means that users experience consistent performance for typical mobile tasks on AU’s network most of the time.

au’s speed performance is mixed. While it shines in 5G download speed and offers a decent 4G download speed, upload speed could be improved across both network generations.

IV. Does KDDI Japan support eSIM?

Yes, au also offers eSIM to compatible devices and the eSIM is also for subscription which means for Japanese residents only.

V. Top KDDI SIM cards for Tourists & Cost

Unfortunately, AU doesn’t have a tourist au by KDDI SIM card, only has subscription data plans, for Japanese residents. Foreigners can subscribe to an AU subscription only if they possess a visa other than a tourist visa.

Luckily, MVNOs (Mobile Virtual Network Operators) offer prepaid plans without contracts, using major networks, including KDDI. MVNOs are perfect for short trips as you don’t commit long-term.

MVNOs rent space on major networks at lower costs, passing savings to customers. They let you easily keep in touch during your stay without postpaid account requirements.

VI. Where to buy KDDI SIM for Japan

You have several 2 methods for buying an au by KDDI SIM card for Japan: in-person or online, depending on your needs and preferences:

• KDDI stores (au shops): These are the official stores for KDDI mobile service. You can find au store in major cities and towns across Japan. They offer a wide range of SIM card plans and can help you choose the right one for your needs.
• Electronics retailers: Many electronics retailers in Japan, such as Bic Camera, Yodobashi Camera, and Yamada Denki, also sell au by KDDI SIM cards or SIMs using the KDDI network.
• Convenience stores: Some convenience stores in Japan, such as Lawson and FamilyMart, also sell KDDI SIM cards. This is a good option if you need a SIM card quickly and easily.
• Online: You can also purchase KDDI SIM cards online from the KDDI website or third-party retailers. This is a good option if you’re not in Japan or if you want to compare prices from different vendors.

VII. Where to buy Japan KDDI eSIM

Finding KDDI Japan eSIM is more limited for foreigners but you can try Japan eSIM from GIGAGO, with KDDI as the supporting network. 

Check out Gigago’s Japan eSIM powered by KDDI – starting from just $7.5 for 14 days of fast LTE data. No roaming fees – simply scan the QR code we email upon purchase. Travel to Japan has never been smoother. Purchase now to explore like a local upon arrival!

VIII. How to top-up KDDI Japan SIM/eSIM

If you start to run short on data or calling balance with your au by KDDI SIM card/eSIM, you have two ways to top-up prepaid credit:

• Online – Revisit the KDDI prepaid portal and log in to add more yen by credit card to your SIM profile
• Stores – Take SIM card to BIC, Yodobashi, or other electronic stores with SIM section to top-up
• Vending – Purchase prepaid voucher cards from AU vending machines and add them to your SIM

So it’s straightforward to add more data & call credit even mid-trip – just monitor your usage in Japan and top-up online when running low.

So au by KDDI SIM cards make it simple to renew your balance from their online account dashboard while traveling in Japan. This allows you to keep enjoying KDDI’s stellar nationwide 4G speeds and coverage while exploring the Land of the Rising Sun!

IX. FAQs about au by KDDI in Japan

X. Conclusion

So in summary, getting a Japan eSIM setup with KDDI network is a great way for tourists on short or extended visits to stay conveniently connected with mobile data and calls across Japan. With affordable prepaid packages, lightning-quick 4G speeds, and near nationwide population coverage, KDDI connectivity keeps your Japan travel adventures flowing smoothly whether hiking Mount Fuji or lost in Tokyo’s neon-lit side streets!