Every "best eSIM for Japan" guide — including ours — is written for someone landing for a week or two. The moment your trip stretches past a month, that math stops working. We live in Japan, and the people who ask us about this are never on a quick holiday. They're on a working holiday visa, a six-month digital nomad visa, a university exchange, or they've just decided to slow-travel for ten weeks instead of ten days. None of the standard 7-day or 30-day eSIM plans fit that, and most comparison articles don't say so.
This is what actually works once "how many days am I here" becomes a three-digit number.
Why the 30-day eSIM breaks down for longer stays
Almost every travel eSIM sold for Japan — the ones in our own eSIM comparison included — caps out at 30 days because that's the window travel-insurance-style data providers are built around. Buy a second one when the first expires and you'll usually pay close to full price again, install a second profile, and in some cases lose any phone number you'd set up on the first one. Do that three or four times over a six-month stay and the "cheap tourist eSIM" stops being cheap, and becomes a monthly chore.
There are three ways around it, and they trade off differently on price, hassle, and how official the underlying plan is.
Option 1: stack the same tourist eSIM back to back
A few providers sell their normal daily-data plan in bundles that go past 30 days, instead of making you re-buy from scratch. Sakura Mobile's eSIM line, for example, runs 1 to 90 days as a single purchase — 3GB/day on the Docomo network for ¥26,400 (about $167 as of November 2026), or truly unlimited 5G on au/KDDI for ¥38,390 (about $243), tax included. Their physical SIM line goes further: a 93-day bundle ships as three stacked 31-day SIMs with a bulk discount built in.
This is the simplest option if your stay fits inside roughly three months: one purchase, one setup, no re-activation mid-trip. The catch is the ceiling — past 90 days, Sakura's own site stops offering a prepaid number and points you toward a residential monthly contract instead, which assumes you already have a Japanese address.
Option 2: a marketplace eSIM built for the long haul
A second tier of providers — eSIM marketplaces rather than single carriers — sell data in 60-, 90-, and even 180-day blocks aimed specifically at long-stay travelers and remote workers. Maya Mobile lists a Japan 5GB/90-day plan at $18.99 and a 20GB/90-day plan at $35.99, plus a 180-day unlimited plan at $389.99. MobiMatter's marketplace carries a Japan 60GB/90-day eSIM running on NTT Docomo for $45.99, and a near-identical KDDI-network version for a few dollars more.
These are worth knowing about, but go in with the right expectations: the plan you're buying is usually resold capacity from a local carrier (Docomo, au, or SoftBank) rather than a plan the carrier sells directly, and the marketplace — not the network — is who you'll be dealing with for support if something goes wrong. For a flat multi-month data allowance with no renewal step, they're genuinely useful. For reliability if your work depends on the connection, we'd lean toward Option 1 or Option 3 instead.
Option 3: get a real, renewing line instead of a bigger one-off
If "long stay" really means indefinite — you don't know yet whether it's three months or a year — the better fit isn't a bigger prepaid block, it's a plan that renews like a normal phone bill. Mobal's eSIM does this: ¥4,950 up front, then from ¥1,650 a month for a real Japanese phone number on the Docomo network, with monthly data tiers from 1GB up to 50GB (and larger add-ons after the first month). No fixed end date, no minimum term, cancel any month you like, and unused data rolls over instead of resetting to zero.
The trade-off is the up-front identity check Mobal requires for a voice-enabled line, and the fact that month-to-month billing only makes sense once you're past the point where a 90-day bundle would've been cheaper outright. As a rule of thumb: under three months, do the arithmetic against Option 1 first; past three months, or if the length of your stay is genuinely open-ended, Option 3 usually wins.
Match the plan to the visa, not just the trip length
The right choice often comes down to which visa you're actually on, not just how many weeks you've blocked out:
| Visa / situation | Typical length | Best starting option |
|---|---|---|
| Tourist visa / visa waiver | Up to 90 days | Option 1 (stacked 90-day plan) |
| Digital Nomad visa | Up to 6 months, no extension | Option 3 (monthly), or Option 1 + a second 90-day block |
| Working Holiday visa | Up to 1 year, fixed, non-renewable | Option 3 (monthly) |
| Student exchange | One semester to a year | Option 3, switching to a campus/carrier SIM if one becomes available locally |
| Open-ended slow travel | Unknown in advance | Option 3 |
Japan's Digital Nomad visa is capped hard at six months with no extension — you have to leave and wait six months before reapplying — and it requires an annual income of ¥10 million or more plus private insurance covering at least ¥10 million in treatment costs, on top of being a national of one of the eligible visa-waiver countries. The Working Holiday visa is simpler in one respect: once granted, it's a fixed one-year stay (available to nationals of around 30 partner countries) that can't be extended either. Either way, the visa clock is the thing that should decide the connectivity plan — not the other way around.
What actually changes once you're past 90 days
A few practical things shift once a stay runs long enough that "eSIM" starts competing with "actual phone contract":
- A Japanese address unlocks cheaper options. The carrier-direct monthly plans that locals use are far cheaper than any prepaid eSIM, but almost all of them require a residence card and a Japanese address to sign up — something a 90-day tourist stay won't have.
- Identity checks get stricter, not looser. Any plan that includes a real phone number — Mobal, Sakura's voice+data tier — requires an in-person or document-based ID check, because a Japanese number is treated as a real registered line, not a throwaway travel SIM.
- Price per gigabyte drops the longer the block. Sorting the numbers above by cost per GB, the 180-day and 90-day bundles consistently beat buying four separate 30-day plans back to back, even before counting the hassle of re-installing each time.
FAQ
Can I just buy four 30-day eSIMs in a row instead?
You can, and some people do, but you'll usually pay close to the full 30-day price each time with no bundle discount, and if you'd paid for a number on the first one, you'll likely lose it when that eSIM expires and you switch to the next. It's the most expensive and most fragile way to cover a long stay.
Do any of these long-stay eSIMs come with a Japanese phone number?
Among the options above, only Mobal's voice+data line reliably does, because it's a renewing monthly plan rather than a prepaid data bundle. Sakura Mobile also sells a voice+data eSIM with an in-person ID check requirement; most 90-day and 180-day marketplace bundles (Maya, MobiMatter) are data-only.
What happens to my eSIM if I leave Japan and come back during a long stay?
A data-only prepaid eSIM keeps running on the calendar, not on presence — a 90-day plan counts down whether you're in the country or not, so a short trip home mid-stay eats into it. A renewing monthly plan like Mobal's doesn't have that problem; you're simply paying (or pausing, if the provider allows it) by the month regardless of where you physically are.
Before you book anything
Work out two numbers before you buy: how many days you're actually staying, and whether that number is fixed or open-ended. A fixed stay under three months almost always favors a single 90-day bundle; an open-ended one favors a renewing monthly line, even though it looks more expensive on day one. If you're also weighing this against a multi-country trip or wondering whether your phone can even run two eSIMs at once, we've covered both separately.
