No Japan eSIM we sell is unlimited at full speed. The “unlimited” Japan plans slow down after a daily allowance, either 1 GB a day or 3 GB a day, and none of them lasts longer than 10 days. For a trip of a week or more, a fixed 30-day plan usually costs less: 20 GB for 30 days is $11.80, against $18.00 for 7 days of unlimited. For a short, heavy trip, unlimited can still be the right buy.
The trap is easy to fall into. “Japan eSIM unlimited” sounds like the safe choice for a two-week trip, so you pay for it, and on day three you are on a Shinkansen with video buffering at a fraction of the speed you expected, because the day’s high-speed allowance ran out before lunch. Here is what each type of Japan plan actually gives you, using the 34 Japan-only listings in our catalogue on 30 September 2026.
- Two kinds of unlimited: 1 GB a day day passes on DOCOMO, then 256 kbps, from $1.99; and Airalo Unlimited on SoftBank and KDDI, 3 GB a day at 20 Mbps, then 1 Mbps, from $9.80.
- Longest unlimited Japan plan: 10 days. There is no 30-day unlimited Japan plan in our catalogue.
- 30-day fixed plans: 5 GB for $5.30 up to 50 GB for $26.88, full speed until the data is used up.
- Hotspot: listed as supported on the Airalo, IIJ and TSimTech plans, and not stated on the DOCOMO plans.
What “unlimited” means on a Japan eSIM
Both unlimited types keep you online all day. What changes is the speed after your daily high-speed allowance is gone.
| Type | High-speed allowance | After that | Network listed | Lengths and prices |
|---|---|---|---|---|
| Japan Day Pass | 1 GB a day, reset at midnight Japan time | 256 kbps | DOCOMO, 4G LTE | 1 to 10 days, $1.99 to $7.00 |
| Airalo Japan Unlimited | 3 GB a day, at up to 20 Mbps | 1 Mbps | SoftBank, KDDI | 3 to 10 days, $9.80 to $22.40 |
So what do those slow speeds let you do? The video services publish their own numbers. YouTube’s help page asks for a connection of 500 Kbps or more to watch at all, about 0.7 Mbps for 360p and 1.1 Mbps for 480p. Netflix recommends 3 Mbps for HD and 15 Mbps for 4K.
- 256 kbps is below YouTube’s minimum. Text messages and email generally still get through, slowly. Video and photo-heavy feeds will struggle.
- 1 Mbps clears YouTube’s 360p figure but not 480p. Maps and messaging are comfortable; video is watchable at low quality.
- 20 Mbps is a ceiling on the Airalo plan, even within the first 3 GB. It is still above Netflix’s 4K recommendation, so you will rarely notice it on a phone.
The 30-day plans: fixed data at full speed
A fixed plan works the other way round. You get one pot of data with no daily limit, used at full speed until it runs out, and then the plan ends. These are the 30-day Japan plans in our catalogue, cheapest per size:
| Plan | Price | Per GB | Network listed | Hotspot |
|---|---|---|---|---|
| 3 GB, 30 days | $6.60 | $2.20 | SoftBank, KDDI | Supported |
| 5 GB, 30 days | $5.30 | $1.06 | DOCOMO | Not listed |
| 10 GB, 30 days | $7.00 | $0.70 | DOCOMO | Not listed |
| 12 GB, 30 days (IIJ) | $9.00 | $0.75 | NTT docomo | Supported |
| 15 GB, 30 days | $10.60 | $0.71 | DOCOMO | Not listed |
| 20 GB, 30 days | $11.80 | $0.59 | DOCOMO | Not listed |
| 30 GB, 30 days | $20.61 | $0.69 | DOCOMO | Not listed |
| 50 GB, 30 days | $26.88 | $0.54 | DOCOMO | Not listed |
Two details on the DOCOMO plans are worth knowing. Their descriptions count validity in calendar days on Japan time: the day you first connect is day 1, and the plan ends at midnight Japan time on day 30. Land at 11 pm and day 1 is nearly gone, so start using the eSIM early in the day if you can. For longer stays, IIJ also offers 35 GB for 60 days at $24.19 and 60 GB for 90 days at $40.32.
Compare every option in one place: the Japan eSIM page lists all our Japan plans, including regional plans that cover Japan, with filters for data, days and unlimited.
Which is cheaper for your trip length
Light use here means maps, messaging, translation and some browsing. Heavy use means video, big uploads or tethering a laptop. Prices are from 30 September 2026.
| Trip | Light use | Heavy use |
|---|---|---|
| 3 days | Day pass, 3 days: $4.00 | Unlimited, 3 days: $9.80 |
| 5 days | 5 GB, 30 days: $5.30 | 20 GB, 30 days: $11.80, or unlimited 5 days: $13.00 |
| 7 days | Day pass, 7 days: $5.89, or 10 GB: $7.00 | 20 GB, 30 days: $11.80 (unlimited 7 days is $18.00) |
| 10 days | 10 GB, 30 days: $7.00 | 30 GB, 30 days: $20.61 (unlimited 10 days is $22.40) |
| 14 days | 10 to 15 GB, 30 days: $7.00 to $10.60 | 30 to 50 GB, 30 days: $20.61 to $26.88 |
| 30 days | 15 to 20 GB: $10.60 to $11.80 | 50 GB: $26.88 |
The 10-day row hides a useful comparison. The 10-day day pass and the 10 GB 30-day plan cost the same $7.00 and both give you 10 GB at full speed. The fixed plan lets you spend 4 GB on a travel day and nothing on a museum day. The day pass makes you pace yourself, but it never runs out completely: after your daily gigabyte you still have 256 kbps for messages. Pick the fixed plan for flexibility and the day pass if you want a guaranteed floor.
If you are not sure which column you are in, our travel data guide estimates usage app by app.
Networks, IP address and hotspot
Each Japan plan lists the network it uses, where its internet traffic exits, and whether hotspot is allowed. They are not all the same:
| Plans | Network listed | IP routing | Hotspot | Starts counting |
|---|---|---|---|---|
| Day passes and DOCOMO fixed plans | DOCOMO, 4G LTE | Japan | Not listed | First data use |
| Airalo Unlimited and 3 GB | SoftBank, KDDI | Not published | Supported | First data use |
| IIJ 12, 35 and 60 GB | NTT docomo | Japan | Supported | When installed |
| TSimTech Short Trip, 3 GB for 5 days | KDDI, SoftBank | Singapore | Supported | First data use |
If you plan to tether a laptop or share data with a travel partner, choose a plan that lists hotspot as supported. “Not listed” means the plan does not state it, so we do not promise it; our hotspot audit explains how to read that field. If you need a Japanese IP address, pick a plan that lists Japan routing; our IP address guide explains what routing does and does not change.
On Android, the DOCOMO plans may need the APN set to vmobile.jp if data does not connect after installing. The product pages show this in the attention note.
When unlimited is the right buy, and when it is not
Unlimited is worth it if:
- Your trip is 3 to 5 days and you will stream, upload or video call a lot. Three days of Airalo Unlimited gives up to 9 GB at 20 Mbps for $9.80.
- You need to tether a laptop on a short work trip. The Airalo Unlimited plans list hotspot as supported.
- You do not want to watch a data counter. The data never stops; only the speed drops until the daily reset.
A fixed plan is the better buy if:
- Your trip is longer than 10 days. No unlimited Japan plan in our catalogue lasts longer than that, so you would have to stack two.
- Your use is light or uneven. A fixed plan lets heavy days borrow from quiet ones.
- You care about speed later in the day. After the daily allowance, 1 Mbps or 256 kbps will not stream video beyond low quality.
- You are travelling as a group and one device should share. Consider whether pocket Wi-Fi suits you better.
Installing, and when the clock starts
Check that your phone supports eSIM and is carrier-unlocked on our compatibility page, then install over Wi-Fi before you fly using the install guide. When you land, switch mobile data to the eSIM and turn on data roaming for that line only.
Most Japan plans here start counting on first data use, so installing early is safe. The IIJ plans are the exception: they start counting when the eSIM is installed, so install those on the day you travel. Our guide to when an eSIM starts counting covers the three activation policies in detail, and the Japan eSIM guide covers the rest of the trip.
Frequently asked questions
Is there a truly unlimited Japan eSIM?
Not unlimited at full speed. Both types we sell slow down after a daily allowance: day passes drop to 256 kbps after 1 GB, and Airalo Unlimited drops to 1 Mbps after 3 GB. Your data never stops, but speed stays low until the daily reset.
Is there a 30-day unlimited Japan eSIM?
Not in our catalogue on 30 September 2026. The longest unlimited Japan plan is 10 days, at $22.40. For a month in Japan, a fixed plan is cheaper: 30 GB for $20.61 or 50 GB for $26.88, both at full speed until the data is used.
How much data do I need for 30 days in Japan?
At about 500 MB a day for maps, messaging and browsing, 15 GB covers a month. Daily video, hotspot use or large photo uploads can reach 2 GB a day, which points to a 50 GB plan. Our travel data guide breaks this down by app.
Does a Japan eSIM use DOCOMO or SoftBank?
It depends on the plan. Our day passes and most fixed Japan plans list DOCOMO, the IIJ plans list NTT docomo, and the Airalo plans list SoftBank and KDDI. Each product page names its networks in the Destinations and networks table.
Can I use hotspot with a Japan eSIM?
Yes, on plans that list it. Hotspot is listed as supported on the Airalo Unlimited and Airalo 3 GB plans, the IIJ plans and the TSimTech Short Trip plan. The DOCOMO day passes and fixed plans do not state hotspot support, so do not count on it there.
When does a Japan eSIM start counting days?
Most of our Japan plans start on first data use, so you can install them days before you fly. The IIJ plans start when installed. The DOCOMO plans count calendar days on Japan time, ending at midnight on the last day.
Unlimited sounds like the safe choice, but in Japan it is a short-trip tool. For most trips of a week or longer, a 30-day plan sized to how you actually use your phone gets you more full-speed data for less.
Last reviewed 30 September 2026. Plan details, speeds and prices come from our own catalogue and product descriptions on that date and change often; product pages are authoritative. The 34 listings are in-stock Japan-only plans, excluding top-up packs; some specifications are offered under more than one listing. Speed guidance is from YouTube’s and Netflix’s own help pages. DOCOMO, NTT docomo, SoftBank, KDDI, IIJ and Airalo are trademarks of their owners; this article is independent of them.