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Disclosure: ESIM KIMONO is our store. Competitor facts come from their own pages and public reviews, checked 13 October 2026, each linked.
Short answer: Ubigi gives you two Japanese networks (NTT Docomo and KDDI), top-ups in its app and plans for many countries. ESIM KIMONO is Japan only, on KDDI, with an unlimited plan that runs at a flat 10 Mbps from the first minute with no daily or total cap, no app, and a human who answers if something goes wrong. Pick Ubigi if you need Docomo in remote areas; pick us if you want one speed rule you can read before paying and a replacement if the eSIM fails.
Day eight of a ten-day trip. You took the train north from Tokyo, and now you're at a station exit in a town you can't pronounce. The map stops loading. The taxi app spins. Your partner is holding the bags, the kids want dinner, and the photos from the morning are still waiting to be posted.
You used Ubigi last time and it mostly worked. Two things made you look again before this trip.
The unlimited plan has a limit. Ubigi's 7-day unlimited plan gives 25GB at full speed, then 2 Mbps (Ubigi plan page). One reviewer: "It is NOT unlimited, it has a cap… (if this is the case please advertise us correctly)." (Trustpilot, Sep 2026)
Dropouts in a big city. "It often randomly just disconnects… sometimes if I toggle the data / SIM on and off, it reconnects." (Osaka, Trustpilot, Jul 2026)
To be fair: Ubigi holds 4.1★ across 48,484 reviews on Trustpilot, with 16.6% at 1 to 2★. Most customers are happy. This page is about which one fits your trip.
| ESIM KIMONO | Ubigi | |
|---|---|---|
| Network | KDDI 4G/5G, a licensed Japanese carrier | NTT Docomo and KDDI |
| Unlimited speed rule | Flat 10 Mbps from the first minute, no daily or total cap | 25GB at full speed (7-day plan), then 2 Mbps |
| Fixed plan after the data is used | 384 kbps until the plan ends, so maps and messages still load | Top up in the app |
| Hotspot | Allowed on most plans; each plan's rule printed at checkout | Not covered in our check |
| Delivery | QR code by email in minutes, no account, no app | Ubigi app and account |
| If the eSIM is faulty | Replaced one for one | Under Ubigi's terms |
| Support | Real humans on chat and [email protected] | Through Ubigi; one reviewer describes an AI assistant loop (below) |
Sources: Ubigi plan pages (10GB / 7 days, unlimited 7 days), Trustpilot, our /fup/, checked 13 October 2026.
We read the newest 1 to 2★ Trustpilot reviews that mention Japan and kept 29 that were about Japan. One review can fit several groups: 15 described no connection, failed activation or dropouts, 8 slow speeds, 5 refunds or billing, 3 unhelpful support and 2 confusing APN setup.
A sample of 29 complaints shows what goes wrong, not how often. Ubigi's overall 1 to 2★ share is 16.6% across all its countries.
That airport queue, passport out, buying a SIM because the eSIM won't wake up, is the moment we built around.
ESIM KIMONO is run by Fizen LLC. Fizen.io has 500,000+ app users and a strategic investment from Tether. Our eSIM is a GSMA standard profile, and card payments run on Stripe (PCI DSS Level 1).
What we can't answer: we haven't published which IP region our eSIMs present, so we make no claim there, and we have no Docomo option. We can't promise zero dropouts; no honest provider can.
Not entirely. Ubigi's 7-day plan gives 25GB at full speed, then 2 Mbps for the rest of the plan (Ubigi plan page, checked 13 October 2026).
We don't compete on price. Plans are priced for a carrier-grade network and a human who answers. Today's price is on the button below.
Both are national licensed networks. Ubigi offers both; we use KDDI. We haven't published our own coverage test, so we won't claim one wins.
Ubigi uses its app and account to manage plans and top-ups. ESIM KIMONO needs no app or account: the QR code arrives by email.
Run the airport rescue card, then message us on chat or at [email protected]. A faulty eSIM is replaced one for one.
Competitor facts on this page were checked on 13 October 2026 on their own pages. The button above shows today's price.
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