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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: Saily is a well-reviewed provider with longer fixed plans, app top-ups and a US number add-on, and its Japan unlimited runs at full speed for 5GB a day, then up to 1 Mbps. ESIM KIMONO runs every unlimited plan at a flat 10 Mbps from the first minute with no daily data cap, on KDDI, with no app. If your workday goes past 5GB, the speed rule matters more than the brand.
You land at Fukuoka Airport on a Monday. The client call is at 10am, the coworking space is two train stops away, and you still need the station map. If the eSIM will not activate, you are in the arrivals hall with your passport out, queueing for a SIM card while the call starts without you.
Say it works. The day runs: two video calls, Slack all afternoon, a few file syncs over your phone's hotspot, a map to dinner. That can pass 5GB before the evening. At 4pm, on a plan that slows after 5GB, the next call stutters and the laptop sync stalls.
What fixes this is not a lower number on a price tag. It is a known carrier, a speed rule you can read before paying, a person who answers when something breaks, and a replacement if the eSIM is faulty.
Saily: "5GB/Day without a speed limit", then "up to 1 Mbps" until the day resets (saily.com). Under 5GB a day, you get full network speed. Past it, 1 Mbps is enough for messages and slow maps, and thin for a video call.
ESIM KIMONO: a flat 10 Mbps from the first minute, all day, with no daily cap. The 9pm call runs like the 9am one. Our fair use page is plain about the limit: 10 Mbps suits calls, Slack, maps and HD streaming on a phone, not large laptop downloads. For heavy download days, our fixed plans run at full network speed, then 384 kbps once the data is used.
So the honest test is your own day. Light days under 5GB favour Saily's full speed. Heavy, steady days favour a flat rule that does not change at 4pm.
| ESIM KIMONO | Saily | |
|---|---|---|
| Network | KDDI 4G/5G, licensed Japanese carrier | KDDI and SoftBank |
| Unlimited speed rule | Flat 10 Mbps, no daily data cap | 5GB a day at full speed, then up to 1 Mbps |
| Fixed plans after data is used | 384 kbps until the plan ends | Top up in the app |
| Hotspot | Most plans; each plan's rule printed at checkout | "Limitless hotspot sharing" |
| App or account | None | Saily app |
| Support channel | Real humans on chat and [email protected] | Chat in the app |
| Faulty eSIM and refunds | Replaced one for one; unused plans refunded under package terms | Per Saily terms |
| Delivery | QR code by email in minutes | In the app |
| Activation window | Printed at checkout | 180 days |
| Trustpilot | No profile yet | 4.7★ from 32,244 reviews |
Sources: saily.com/esim-japan, Trustpilot, our /fup/.
Saily's record is strong, and we say so. Still, the complaints show what a trip feels like when things go wrong. From the newest 1-2★ Trustpilot reviews mentioning Japan, pulled 13 October 2026, we kept 26. Fourteen involved no connection, activation failure or dropouts. Eleven mentioned slow or throttled data. Twelve mentioned refunds or billing. Two said data appeared to route through Hong Kong.
That is a negative sample against a 4.7★ average. It shows what can go wrong, not how often. On routing: two reviews are not a measured rate, and we have not published our own eSIMs' IP region, so we make no claim there. If a Japanese IP matters for banking or region-locked work, test on day one with any provider.
Setup is a QR code by email in minutes, no account, no app. Install it on home Wi-Fi before you fly. Card payments run on Stripe (PCI DSS Level 1). The store is run by Fizen LLC; Fizen.io has 500,000+ app users and a strategic investment from Tether.
Saily gives 5GB a day at full speed, then up to 1 Mbps until the day resets (saily.com, checked 13 October 2026). ESIM KIMONO's unlimited is a flat 10 Mbps with no daily data cap.
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.
Two reviewers in our 26-review sample reported it. We have not measured it, and we make no claim about our own IP region.
Saily works through its app. ESIM KIMONO sends a QR code by email, with no app and no account.
Saily advertises limitless hotspot sharing. Hotspot works on most of our plans, and each plan's rule is printed at checkout.
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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