The only 30GB plan · Docomo and KDDI · a review history
Yesim in Japan
Yesim publishes two of the three good Japanese networks and sells a size nobody else does. It also had its Trustpilot score switched off during a fake-review cleanup, and we are going to keep saying so.
Every Yesim Japan plan USD, checked September 2026
| Plan | Price | Per GB | Notes |
|---|---|---|---|
| 1GB / 30 days | $4.30 | $4.30 | The longest window at 1GB. GigSky's is $2.99 for a week. |
| 5GB / 30 days | $10.23 | $2.05 | Cheapest 5GB with a full month of validity. |
| 10GB / 30 days | $18.59 | $1.86 | The most expensive 10GB of the four we link. |
| 20GB / 30 days | $28.82 | $1.44 | Saily is $24.99 and Airalo $25.00 for the same size. |
| 30GB / 30 days | $38.35 | $1.28 | Nobody else sells 30GB for Japan at any price. |
| Unlimited / 1 day | $4.07 | — | Yesim states a fair usage policy and never publishes the daily figure. You cannot know what you bought. |
| Unlimited / 2 days | $8.13 | — | |
| Unlimited / 30 days | $63.91 | — |
Yesim lists thirteen single-country Japan plans and twenty-five multi-country options that include Japan; the rows above are the ones worth comparing. All plans are data-only with no SMS. Prices in USD, checked September 4, 2026.
Yesim publishes KDDI and NTT Docomo which is more than most
Of the four brands we can link, only two publish an NTT Docomo agreement: GigSky and Yesim. Docomo is the network with the deepest rural and mountain coverage in Japan, and outside the cities it is the whole decision. The network page explains why.
Yesim's combination, KDDI plus Docomo, is on paper the best of the four: the two strongest networks, no SoftBank filler. It is the same pairing Ubigi holds, and Ubigi is the brand every AI assistant recommends for exactly that reason.
So why is Yesim not our default pick? Price and record. It is the most expensive 10GB of the four, its 20GB is nearly four dollars above Saily's, and it is the one brand here with a review history worth a paragraph of its own. If you want Docomo cheaply, GigSky is $16.79 for 10GB against Yesim's $18.59. Yesim earns its place at 30GB, where it has no competition, and at 5GB over a full month.
The Trustpilot history, in full because you should hear it from us
Where it stands now. As of September 4, 2026 the score is displayed again: 4.3 out of 5 across 2,942 reviews, with replies to 91 per cent of negative reviews. We checked the page twice on the day this was written, from two different tools, and found no suspension notice or consumer alert on it.
What we take from that. The enforcement worked and the profile came back clean, on the same review count it had during the suspension. That is a reasonable outcome and it is not the same thing as never having happened. A company whose reviews were once cleaned out from under it is a company that once had an incentive to game them.
What we do about it. Yesim stays on the site, its prices stay in every table, and this history is written next to it every time it appears. Yesim pays this site 18 per cent, the second highest rate of any brand we work with, which is precisely why we are not going to quietly stop mentioning the history. Compare that with Saily's 4.7 across 30,542 reviews, which has never had anything of the kind attached to it.
Yesim against the other three size by size
| Yesim | GigSky | Airalo | Saily | |
|---|---|---|---|---|
| 1GB | $4.30 / 30d | $2.99 / 7d | $4.00 / 3d | $3.99 / 7d |
| 5GB / 30 days | $10.23 | $10.29 | $11.00 | $10.99 |
| 10GB / 30 days | $18.59 | $16.79 | $18.00 | $17.99 |
| 20GB / 30 days | $28.82 | none | $25.00 | $24.99 |
| 30GB | $38.35 | none | none | none |
| Unlimited, 30 days | $63.91 | none | $69.00 | $71.99 |
| Unlimited cap published | no | 3.5GB/day in the name | 3GB/day, 1 Mbps | 5GB/day |
| Japanese networks | KDDI + Docomo | Docomo + SoftBank | KDDI + SoftBank | not published |
| Trustpilot | 4.3 · 2,942¹ | 4.3 · 6,217 | 4.1 · 41,885 | 4.7 · 30,542 |
¹ Score restored after a fake-review suspension. See the section above.
Yesim wins three rows: cheapest 5GB with a full month, the only 30GB, and the cheapest thirty days of unlimited. The unlimited win comes with an asterisk the size of the plan, because Yesim will not say how much full-speed data a day it includes, and a cheaper unlimited plan with an unknown cap is not obviously cheaper at all.
Buying and activating Yesim and one checkout quirk
- Buy on the Yesim website at home on wifi and check the currency selector. Reviewers have reported small unexpected charges at checkout when the display currency and the card currency differ, so confirm the total before you confirm the payment.
- Know what you are buying. If you take an unlimited plan, understand that the daily allowance is not published anywhere. If that bothers you, and it should, Airalo prints 3GB a day and 1 Mbps.
- Install the profile before you fly. It does not start counting until it connects in Japan.
- On landing: Yesim line on for data, home line on for calls with data roaming off. If it will not attach, set network selection to manual and pick NTT Docomo, then KDDI. Full setup and fixes.
Buy Yesim if, skip it if the short version
Buy it if
- You want 30GB. Nobody else sells it for Japan, and $38.35 is $1.28 a gigabyte.
- You want 5GB with a full month of validity at the lowest price, $10.23.
- You want Docomo and KDDI on one profile from a brand we can actually link.
- You have read the Trustpilot section and decided the history does not change your mind.
Skip it if
- You want 10GB or 20GB. GigSky and Saily are cheaper for both, by $1.80 and $3.83.
- You want unlimited with a cap you can plan around. Yesim publishes no daily figure at all.
- The review history bothers you. That is a reasonable position and Saily at 4.7 across 30,542 exists.
- You want a free trial before committing. Only GigSky offers one.
Yesim Japan questions short answers
Is Yesim safe to use for Japan?
It sells real plans on real networks and people use it without incident. The history to know: Trustpilot suspended its score during a fake-review enforcement action and has since restored it, showing 4.3 across 2,942 reviews as of September 4, 2026. That is a recovered profile rather than an unblemished one, and we say so in every table it appears in.
Which network does Yesim use in Japan?
KDDI (au) and NTT Docomo, per its published Japan coverage record. On paper that is the best pairing among the four brands we can link, since it is the two strongest Japanese networks with no SoftBank filler. GigSky is the other brand here with Docomo, and it is cheaper at 10GB.
Does Yesim have unlimited data for Japan?
Yes, from $4.07 for a single day to $63.91 for thirty, which is the cheapest month of unlimited among the brands we link. It is also the only one where the daily allowance is not published anywhere. Yesim states a fair usage policy and gives no number, so you cannot know at what point it slows down.
What is the cheapest 30GB eSIM for Japan?
Yesim's, at $38.35 for 30 days, because it is the only brand selling 30GB for Japan among those we track. The nearest alternatives are Saily's 20GB at $24.99 or Ubigi's 60GB at $45.00, which we cannot link.
Is Yesim cheaper than Airalo for Japan?
At 5GB yes, $10.23 against $11.00 for the same thirty days. At 10GB no, $18.59 against $18.00. At 20GB no, $28.82 against $25.00. Yesim's genuine price wins in Japan are 5GB, 30GB and thirty days of unlimited.
The only 30GB plan sold for Japan
$38.35 over thirty days on KDDI and NTT Docomo. Yesim pays this site 18 per cent, the second highest rate of any brand we work with, and its Trustpilot score was once suspended during a fake-review cleanup. Both of those facts are on this page on purpose.
See Yesim Japan plansSources & freshness: Plan prices from Yesim's Japan listing via esimdb on September 4, 2026, in USD, before promo codes. Network permissions from Yesim's published Japan coverage record on the same date. Trustpilot 4.3 across 2,942 reviews, checked twice on September 4, 2026 with no suspension notice present; the earlier suspension during a fake-review enforcement action is recorded in our own provider notes from August 2026. Checkout currency reports come from third-party reviews. How we test.