The network, named

Japan eSIM on the KDDI Network: What You Actually Get

Most travel eSIM stores sell a mystery network. Ours is KDDI, one of Japan's largest mobile carriers, named on the box.

What KDDI is

The carrier behind the au brand: nationwide 4G LTE, 5G in and around the cities, tens of millions of Japanese phones every day. A travel eSIM on KDDI rides the same towers.

Coverage, honestly

In every city a tourist sleeps in, all three Japanese networks are simply good. Differences live at the margins: deep valleys, long tunnels, backcountry. There KDDI holds its own, and no honest seller promises bars everywhere on any network.

5G, without the theater

You get KDDI 5G where the phone and the tower both speak it, mostly metro areas, with 4G LTE everywhere else. Japanese 4G beats most hotel Wi-Fi. Buy days and data, not the letter G.

The speed rules, all of them

Fixed plans: full speed, then 384 kbps after the bucket. Unlimited: no bucket, flat 10 Mbps cap. Both printed at checkout. No hidden daily ceiling on top.

KDDI vs Docomo vs Softbank paths

In cities you will not tell them apart in a blind test. The real difference is whether the seller names the network at all. Ask any store two questions: which network, and what happens after the high speed data. Our answers are on this page; the comparison guide linked below prices all of us on the same day.

Straight answers

Is KDDI good for tourists in Japan?

Yes. KDDI is one of Japan's largest carriers, with 4G everywhere tourists go and 5G in metro areas. In the cities all three networks perform; real differences live at the rural margins.

Is au the same as KDDI?

au is KDDI's consumer brand, the same network. A plan described as au and a plan described as KDDI ride the same towers.

Does a KDDI eSIM support 5G?

Yes, where the phone and the local tower both support it, mostly in and around cities, with 4G LTE as the fallback everywhere else.