The methodology and the money, on one page
How we test, and what we earn
A comparison site that hides its incentives is an advertisement. Here is exactly where the numbers come from, what we have not done, and who pays us what.
What we earn, brand by brand the actual rates
| Brand | We earn | Where it appears on this site |
|---|---|---|
| GigSky | 20% | The default pick, because it is the only linkable eSIM on NTT Docomo and the cheapest 10GB. It is also our highest rate, so read the reasoning and decide for yourself. |
| Yesim | 18% | Cheapest 5GB with a month's validity and the only 30GB plan for Japan. Flagged every time with its Trustpilot suspension history. |
| Saily | 15% | The unlimited and hotspot pick, for the largest published daily cap in Japan and the best support record on the site. |
| Airalo | 12% | The corridor pick and the cheapest 20GB. Our lowest rate and still the recommendation for most first trips that stay in the cities. |
| Drimsim | fixed fee | One page only, the phone number page, where we say plainly that it is the weakest of the three options for that problem. |
| Ubigi | nothing | Reviewed in full on its own page and listed in every comparison table. Best network access in Japan and cheaper than us at 10GB and 20GB. |
| Nomad | nothing | Listed in the comparison tables because its prices are real and sometimes the lowest. |
| Mobal | nothing | Named as the practical route to a Japanese phone number, unlinked, because it is the honest answer to that question. |
| Pocket wifi renters | nothing | We wrote a page saying when to rent a router instead, which costs us the sale. |
All commissions come through the Travelpayouts network. The rate never changes your price, and it has never changed the order of a recommendation. The test we apply: strip the commission out and does the reasoning still hold. If the answer is no, the recommendation changes.
Where the prices come from and why they carry a date
Plan prices are pulled from esimdb.com's per-brand Japan tables and cross-checked against each provider's own Japan product page, in USD, before any promotional code. The full pull for this site was done on September 4, 2026 and covers 56 plans across six providers.
One complication worth naming: Airalo's own Japan page geo-serves local currency depending on where you open it, and from our connection it serves Canadian dollars. Its USD figures on this site therefore come from the esimdb table rather than from Airalo's page, and its unlimited cap of 3GB a day is quoted directly from Airalo's own FAQ text.
Every table on this site carries the date it was checked. Prices in this category move by a dollar or two a month and occasionally more when a brand restructures its packages, which Airalo did for Japan between our August and September checks. If a number on your screen does not match a number here, the date at the top of the table tells you how much to trust ours.
Network claims: published, or we say "not published" no guessing
This is the rule the whole site is built on. Every claim about which Japanese carrier a provider rides comes from that provider's own published coverage record, on the date shown. Where a provider publishes nothing, the tables say not published.
We do not repeat network claims from blogs, from database entries or from other comparison sites, because those propagate. Saily is the clear case: third-party listings say KDDI, Saily itself says nothing, and every table on this site says "not published" as a result. That is less satisfying than an answer and it is the truthful thing to write.
Traveler reports are labelled as traveler reports. The Hong Kong exit-address observation on Saily's Japan traffic appears in three places on this site and is described as a reviewer report every time, because that is what it is.
What we have not done said plainly
What we have done: pulled and normalised every plan we can verify, read every fair-use page, checked every Trustpilot profile on the same day, read the text of the April 2026 amendment to the Mobile Phone Improper Use Prevention Act rather than a summary of a summary, and priced pocket wifi from the renters' own rate cards rather than their headline rates.
Those are different kinds of work and we are not going to blur them. A price we pulled is a fact. A coverage note is a well-sourced judgement. A speed test we did not run is not evidence at all, and it will not appear on this site dressed up as one.
The five rules the ones that cost us money
- Unmonetised providers appear in every table. Ubigi has the best network access in Japan and is cheaper than anything we sell at 10GB and 20GB. It is in every comparison on this site with the reason next to it.
- One real drawback per recommendation. Every pick card on this site names a genuine reason not to buy it. If we cannot find one, we have not looked hard enough.
- Fair-use caps are published or marked missing. "Unlimited" is a daily allowance in Japan, and where a brand will not give the number, the table says so rather than leaving the cell empty.
- Every price carries a date. No exceptions, including in the FAQ answers.
- We say when the answer is not to buy anything from us. Rent a router if there are three of you. Buy Ubigi if you need 20GB. Get a Mobal SIM if you need a phone number. Those pages exist and they cost us the sale.
Corrections and what happens to them
If a price here is stale, a network claim is wrong, or your experience on a Japanese network contradicts our coverage table, we want to hear it. The coverage notes in particular rest on published maps and traveler reports rather than on our own measurement, and a specific report from a specific place is worth more than another map.
Verified corrections ship in the next update and we note what changed. Send them here.
Sources & freshness: Commission rates are the current Travelpayouts programme rates for this account, checked September 4, 2026, and are published here rather than described vaguely. Plan data: 56 plans across GigSky, Airalo, Saily, Yesim, Ubigi and Nomad, pulled September 4, 2026. Trustpilot scores checked the same day. About this site · Contact.