Six plans · four caps · two brands that will not say
Unlimited eSIM for Japan
Every unlimited plan sold for Japan is a daily allowance with a throttle behind it. This page puts all of them in one table, in hours of video rather than gigabytes.
Every Japan unlimited cap in one table published numbers only
| "Unlimited" plan | Real daily high-speed cap | After the cap |
|---|---|---|
| Saily Unlimited · $18.99 (5 days) to $71.99 (30 days) | 5GB/day | The largest published daily allowance sold for Japan. Saily states that the connection is reduced for the rest of the day and does not name the reduced speed. Seven lengths available, from five days to thirty, which is the most granular ladder here. |
| Airalo Moshi Moshi Unlimited · $11.50 (3 days) to $69.00 (30 days) | 3GB/day | Then 1 Mbps until midnight. Airalo is the only brand in this comparison that publishes both the allowance and the throttled speed. One megabit still carries maps, LINE, transit apps and voice calls; it does not carry video or a laptop hotspot. |
| GigSky daily packs · $3.49 (1 day) to $44.99 (15 days) | 3.5GB/day | Not sold as unlimited at all. The cap is printed in the plan name, which is the honest version of the same product. It is also the only daily-cap plan for Japan that runs on NTT Docomo. |
| Ubigi Unlimited · $39.00 (15 days) · unlinked | none published | The cheapest fifteen days of unlimited in Japan, on the best network access in the country, and we earn nothing if you buy it. Ubigi publishes no daily figure. The full Ubigi review is here. |
| Nomad Unlimited · from $25.00 (7 days) · unlinked | 2GB/day | Then 1 Mbps. The smallest cap on this table by some way. Two gigabytes is roughly an hour of high-definition video, so this is a maps-and-messaging plan with an unlimited label on it. |
| Yesim Unlimited · $4.07 (1 day) to $63.91 (30 days) | none published | Yesim states a fair usage policy and never gives the number. It is the cheapest month of unlimited among the four brands we can link, and the only one where you cannot know what you bought before you buy it. |
Figures from each brand's own published terms on September 4, 2026. A daily cap resets at midnight in Japan time, not at the moment you bought the plan, which means the first day of a plan bought at 22:00 gives you two hours of allowance.
If you are buying unlimited, buy the largest number anyone will print. Saily's 5GB a day is 67 per cent more full-speed data than Airalo's 3GB, and infinitely more than the two brands that publish nothing.
See Saily unlimited Read the Saily reviewWhat each daily cap is in hours gigabytes are not a unit anyone thinks in
"5GB a day" means nothing until you know what you would spend it on. Rough figures, at the quality settings phones default to on cellular:
| Daily cap | HD video | Video calls | Maps, LINE, photos |
|---|---|---|---|
| 5GB · Saily | ≈4–5 hours | ≈8 hours | a whole day of anything, plus a film |
| 3.5GB · GigSky packs | ≈3 hours | ≈6 hours | a whole day of anything, plus a couple of episodes |
| 3GB · Airalo | ≈2.5 hours | ≈5 hours | a whole day of anything, comfortably |
| 2GB · Nomad | ≈1.5 hours | ≈3 hours | a whole day of anything, just about |
Approximate, and generous to the caps rather than to us: video at roughly 1GB an hour for 720p and more at 1080p, video calls at about 600MB an hour, sightseeing use at 400 to 700MB a day. Your numbers will differ.
Read that table honestly and the conclusion is uncomfortable for the whole product category. Every one of these caps covers a normal sightseeing day with room to spare. If you are not streaming video or tethering a laptop, you are not going to reach 2GB, let alone 5GB, and you are paying two to three times the price of a fixed bucket for a ceiling you will never touch.
Price per day, and price per gigabyte you will actually use the real comparison
| Plan | Total | Per day | Per GB if you max the cap |
|---|---|---|---|
| Saily unlimited, 7 days | $28.99 | $4.14 | $0.83 |
| Saily unlimited, 30 days | $71.99 | $2.40 | $0.48 |
| Airalo unlimited, 5 days | $17.00 | $3.40 | $1.13 |
| Airalo unlimited, 30 days | $69.00 | $2.30 | $0.77 |
| GigSky 3.5GB/day, 7 days | $24.49 | $3.50 | $1.00 |
| Ubigi unlimited, 15 days · unlinked | $39.00 | $2.60 | cap not published |
| Yesim unlimited, 30 days | $63.91 | $2.13 | cap not published |
Two things fall out of that table. Saily at thirty days is the cheapest full-speed gigabyte in Japan, at 48 cents, if and only if you genuinely use five gigabytes every single day. And Ubigi's fifteen days at $39.00 undercuts Saily's $48.99 and Airalo's $48.00 for the same window, on better networks, with no published cap and no commission for us.
When a fixed bucket beats every unlimited plan which is most of the time
Put plainly: unless you are streaming video daily, tethering a laptop for work, or uploading photo and video files every night, a fixed plan is cheaper and there is nothing to think about. The data calculator works out which size you need.
The cases where unlimited genuinely wins:
Remote work. A tethered laptop with video calls runs 2 to 3GB a day on its own. Over two weeks that is 30 to 40GB, which no fixed plan we can link even sells. Saily's fifteen-day unlimited at $48.99 is the answer.
Short and heavy. A five-day trip where you will stream on the Shinkansen every day. Airalo's five days at $17.00 with 3GB a day is $3.40 a day for a ceiling you will actually reach.
Not wanting to think about it. A legitimate reason. If checking a data balance would put a small grey cloud over your holiday, paying $25 extra to never do it is a rational purchase and we are not going to talk you out of it.
Which unlimited plan to buy if you have decided you want one
Saily
The largest published cap in Japan $28.99 unlimited, 7 days, 5GB/day- 5GB a day at full speed, 67 per cent more than Airalo and the biggest number published for Japan
- Seven lengths from five days to thirty, so a nine-day trip does not have to buy fifteen
- Trustpilot 4.7 from 30,542 reviews, the best record on this site
Watch out: Saily does not publish the throttled speed after the cap, and it does not publish which Japanese network it uses either.
Trustpilot 4.7/5 · 30,542 reviews
See Saily unlimited plansAiralo
The only one with both numbers printed $17.00 unlimited, 5 days, 3GB/day- 3GB a day, then 1 Mbps, both published, so you can plan around the ceiling instead of discovering it
- Cheapest short unlimited: three days for $11.50 and five for $17.00
- On KDDI and SoftBank, both published, both strong along the corridor
Watch out: The 3GB cap is two thirds of Saily’s for a similar daily price, and there is no NTT Docomo.
Trustpilot 4.1/5 · 41,885 reviews
See Airalo unlimited plansGigSky
The honest version: the cap is in the name $24.49 3.5GB/day, 7 days- Sold as a 3.5GB-per-day pack rather than dressed up as unlimited
- The only daily-cap plan for Japan that runs on NTT Docomo
- Free 100MB first, so you can test the network before committing to fifteen days of it
Watch out: Expensive per day at short lengths, and fifteen days at $44.99 is the longest it goes.
Trustpilot 4.3/5 · 6,217 reviews
See GigSky daily packsAnd the one we cannot sell you: Ubigi's fifteen days at $39.00 is cheaper than both Saily and Airalo for the same window, on NTT Docomo and KDDI, with no published daily cap. If price and network are what you care about and the missing cap does not bother you, that is the plan to look at, and we earn nothing from it.
Unlimited Japan eSIM questions short answers
Is there a truly unlimited eSIM for Japan?
No. Every plan sold with the word unlimited on it for Japan is a daily allowance with a throttle behind it. The published caps are 5GB a day from Saily, 3.5GB from GigSky's daily packs, 3GB from Airalo and 2GB from Nomad. Yesim and Ubigi publish no figure at all.
Which unlimited eSIM has the biggest cap in Japan?
Saily, at 5GB per day at full speed. That is the largest allowance any brand publishes for Japan, and it is roughly four to five hours of high-definition video or a full working day of a tethered laptop. Prices run from $18.99 for five days to $71.99 for thirty.
Is unlimited data worth it for Japan?
Only if you use more than about 670MB a day over a month, or 1.4GB a day over two weeks. A normal sightseeing day of maps, messaging, translation and photos is 400 to 700MB, so most visitors are better off with a 20GB fixed plan at $24.99. Unlimited earns its price for remote work, daily streaming and heavy hotspot use.
What happens when you hit the daily cap?
Your speed drops for the rest of that day and resets at midnight Japan time. Airalo is the only brand here that publishes the reduced speed: 1 Mbps, which still carries maps, messaging, transit apps and voice calls but not video. Saily says only that the connection is reduced. Yesim and Ubigi say nothing.
Does unlimited data include hotspot in Japan?
On the plans we link, yes, with no separate hotspot ceiling, so the daily cap is shared between the phone and anything tethered to it. That matters: a laptop on a video call can spend a 3GB daily allowance in an afternoon. If you plan to tether daily, take the 5GB cap rather than the 3GB one.
5GB a day, in writing
The largest published daily allowance sold for Japan, in seven lengths from five days to thirty. If you are not going to use more than about 1.4GB a day, buy the 20GB bucket at $24.99 instead and keep the difference.
See Saily unlimited plansSources & freshness: Caps and prices from each brand's own published Japan plan details on September 4, 2026, in USD, before promo codes. Airalo's 3GB-a-day and 1 Mbps figures are quoted from its own FAQ text. Where a brand publishes no daily figure this page says so rather than estimating one. Hours-of-video figures are approximations at common cellular quality settings and are deliberately generous to the caps. We have not run throttle tests in Japan and will say so until we have. How we test.