Last verified: August 14, 2026, against each provider’s own website.
Most Japan eSIM comparisons rank providers by price. Price is the least useful thing to compare, because the plans are within a few dollars of each other and none of them will ruin your trip.
Three things will:
- You assumed you would have a phone number. You will not.
- You bought “unlimited” and got throttled on day two.
- You are travelling with someone and expected to share the connection.
Here is what each provider actually publishes, taken from their own pages.
1. Only one provider gives you a Japanese phone number
Every major travel eSIM for Japan is data only. No calls, no SMS, no Japanese number. This is stated plainly by each company:
| Provider | Calls / SMS | Japanese number |
|---|---|---|
| Airalo | No — “Data-only eSIM” | No |
| Ubigi | No | No — “You will not get a new mobile phone number” |
| Holafly | No | No — “does not include a local phone number” |
| Nomad | No | No |
| Saily | Paid add-on | No — the add-on is a US (+1) number |
| Mobal | Yes | Yes — 070 / 080 / 090 |
Watch the Saily one. Saily’s Japan page lists “Calls: Yes / SMS: Yes”, which reads like you get a Japanese line. You do not. Their own phone-number page says: “Saily phone number provides a US-based phone number.” If you buy it expecting to call a Kyoto restaurant, you will be calling from an American number.
Do you actually need a Japanese number?
For most trips, no. Maps, translation, messaging apps and IC-card top-ups all work on data alone.
You need one if:
- You are booking restaurants that only take phone reservations. A large share of good Kyoto places still do, and many will not take a booking from an overseas number.
- You need to receive an SMS verification code from a Japanese service.
- You are staying long enough that a delivery company or a hotel may need to reach you.
Mobal’s voice plans start at ¥4,950 up front plus ¥990 per month (tax included) for their Voice Lite line — a number, calls and SMS, with data deliberately not included. Their voice products require passport ID verification, so they are not instant. If you want a number, order before you fly.
2. “Unlimited” always has a daily cap
Every unlimited plan is unlimited in the sense that it never stops working. It is not unlimited at full speed. Each provider publishes a daily allowance and a throttled speed after it:
| Provider | Full-speed allowance | After that |
|---|---|---|
| Saily | 5 GB / day | up to 1 Mbps |
| Ubigi (8-day) | 5 GB / day | 2 Mbps |
| Ubigi (30-day) | 60 GB total for the plan | 2 Mbps |
| Airalo | 3 GB / day | 1 Mbps |
| Nomad | 2 GB / day | 1 Mbps (see note below) |
| Holafly | Not published | Not published |
1 Mbps is enough for maps, messaging and email. It is not enough for comfortable video. If you watch anything on the train, assume you are working inside the daily allowance, not outside it.
Holafly is the outlier here, and not in a good way. They describe a fair usage policy but publish no daily figure and no throttled speed. Everyone else tells you the number. That is a reason to prefer the others, independent of price.
3. The tethering trap
This is the one that catches couples and families, and almost no comparison page mentions it.
Holafly’s unlimited plan limits sharing to 1 GB per day. Their own wording: “Share 1 GB of data per day with family, friends, or fellow travelers.” So if your plan is “one person buys unlimited, the other tethers off it,” you have effectively bought a 1 GB per day plan for the second person.
Mobal’s unlimited data eSIM also caps tethering explicitly — for example the 16-day plan allows 15 GB of tethering, after which the tethered device (not your phone) drops to 128 kbps.
Airalo, Ubigi, Nomad and Saily all say hotspot use is allowed and publish no separate tethering cap. That does not mean it is infinite — your daily allowance still applies — but there is no second, smaller limit hiding underneath.
If two of you are sharing one connection, buy two smaller plans rather than one unlimited plan. It is usually cheaper and it removes the failure mode where one phone goes flat and both of you are offline.
4. Your eSIM may start counting down without you
All of these plans start when the eSIM first connects to a Japanese network, which is what you want. But if you buy early and then do not travel, several providers will start the clock anyway:
| Provider | If you never activate it |
|---|---|
| Saily | Auto-activates 30 days after purchase |
| Nomad | Auto-activates on day 60 |
| Ubigi | Expires 6 months after purchase if unactivated |
Practical rule: do not buy your eSIM more than a few weeks before you fly. There is no benefit to buying early, and with Saily a trip booked two months out and an eSIM bought on the same day means the plan is gone before you land.
5. Which Japanese network are you actually on?
This matters in rural areas and mountains far more than in cities. In Kyoto and Tokyo all three networks are fine.
- Airalo: SoftBank and KDDI. Docomo is not listed.
- Ubigi: KDDI and NTT Docomo.
- Holafly: KDDI and SoftBank.
- Nomad: KDDI au and SoftBank. Their 20 GB and 50 GB plans are KDDI au only.
- Saily: not published. They say only that they connect to local carriers.
Docomo historically has the widest rural coverage. If your itinerary is city-to-city, ignore this section. If you are going into the Kiso valley, Shikoku or northern Tohoku, a plan that includes Docomo is worth a small premium.
6. So what should you buy?
Not a ranking — a decision.
- Normal city trip, one person, one to two weeks: any of Airalo, Ubigi, Nomad or Saily. Buy a metered plan of 10–20 GB rather than unlimited; at 2–5 GB per day of full speed, unlimited is only worth it if you genuinely stream.
- Two people sharing: two separate small plans, not one unlimited. Avoid Holafly for this specifically, because of the 1 GB per day sharing cap.
- Going deep into the countryside: prefer a plan that lists Docomo — Ubigi among the above.
- You need to phone restaurants, or need a Japanese number for any reason: Mobal is the only option here, and it needs ID verification, so order it before you leave.
- You want a number and data: Mobal voice plus data, or Mobal voice plus a cheap data eSIM from anyone else. The second is often cheaper — check both against your actual data use.
Where the providers’ own pages contradict themselves
I would rather flag this than pretend the sources are clean.
- Nomad states the throttled speed as 1 Mbps in its plan codes and help centre, but 512 kbps in the description text on the same Japan page. Assume the slower figure when planning.
- Mobal gives two different activation deadlines — “by the end of the second month after dispatch” on the product page, “within 30 days of purchase” in the help centre. Ask them before you rely on either.
- Ubigi‘s product page says an unactivated plan expires after 6 months; an older help article reads as 30 days.
- Saily’s comparison table against other providers is Saily’s own marketing material. Their own footnote says they are unaffiliated with the services being compared. Do not treat it as neutral.
Sources
All figures above come from the providers’ own pages, checked on August 14, 2026:
- Airalo — Japan eSIM
- Ubigi — Japan unlimited and network partner list
- Holafly — Japan eSIM
- Nomad — Japan eSIM
- Saily — Japan eSIM and Saily phone number
- Mobal — Japan SIM and Mobal eSIMs
I live in Kyoto and check these pages against the Japanese-language originals where they exist. Prices and fair-use limits on this page change often — if you find something here that has gone stale, tell me and I will correct it and note the date.