You land at Narita just before nine at night, clear immigration faster than you expected, and then stop dead in the arrivals hall — because the hotel address, the last train time and the friend waiting in Shinjuku all live behind a data connection you don’t have yet. Japan is a country where almost everything runs smoothly and almost nothing is signposted in a language you read.
There are five realistic ways to fix that: an eSIM, a physical prepaid SIM, a rented pocket WiFi, international roaming, or living off free public WiFi. This guide compares all five on cost, speed, setup and the things that actually go wrong, then walks through each one in detail — including what to do after you buy, which is where most travellers trip up.
The 30-second answer
Find yourself below. The detail is further down if you want to check the reasoning.
Cheapest per day, nothing to collect, nothing to return. Only condition: your phone must support eSIM.
Japan Pocket Wifi Rental
Japan eSIM : Fast & Easy & UNLIMTED
Japan Travel eSIM
One device, one bill, up to about ten phones and laptops on it. Everyone stays connected without buying separate plans.
The only option with zero compatibility risk. If your phone can join a WiFi network, it works.
Monthly unlimited router for real work; a SIM with SMS if you need to receive verification codes.
How much data do you actually need?
Most people either massively overbuy or panic-buy the cheapest plan and end up throttled on day three. The honest answer is that Japan travel is a low-data activity punctuated by high-data moments: maps and messaging barely register, while an evening of scrolling short video can eat more than the entire rest of your day.
| What you’re doing | Rough data per hour |
|---|---|
| Messaging, LINE, email | A few MB — effectively free |
| Google Maps navigation | Around 5–10 MB |
| Web browsing, checking timetables | Around 60–150 MB |
| Scrolling social feeds and short video | Around 0.5–1 GB |
| Streaming video in HD | Around 1–3 GB |
| Video calls home | Around 0.5–1.5 GB |
Rough guide only — real usage varies by app, resolution and how aggressively your phone syncs in the background.
In practice: a week of navigating, searching restaurants and posting a few photos lands most travellers somewhere around 5–10 GB. Add regular video calls or a nightly habit of watching things on the train and 20–30 GB is more realistic. If you’d have to think about it, an unlimited plan removes the decision entirely and usually costs less than the anxiety is worth.
Before you land: turn off automatic photo backup and app updates over mobile data, and download offline maps for the cities you’re visiting. That one change does more for your data budget than any plan upgrade.
The five options, side by side
| Option | Best for | Typical cost | Setup | The catch |
|---|---|---|---|---|
| eSIM | Solo travellers, couples, last-minute trips | From ¥2,800 (5 days unlimited) | Buy online, scan a QR code on arrival | Your phone must support eSIM; no refund once activated |
| Prepaid SIM | Phones without eSIM support | From about ¥3,900 | Collect at the airport or your hotel, swap the card | Your phone must be unlocked and support Japanese bands; you lose your home number |
| Pocket WiFi | Groups, families, laptops, long stays | Daily rate short-term; from ¥4,600/month long-term | Turn it on, join the network | Another device to carry, charge and return |
| Roaming | Very short trips, or as a stopgap | Roughly ¥1,000–2,000 per day | Toggle it on before you fly | By far the most expensive, and often capped at a couple of GB a day |
| Free WiFi | Nobody, as a primary plan | Free | Register, log in, log in again | Patchy, slow when busy, and not somewhere to type card details |
eSIM: the default for most travellers
An eSIM is a SIM card that arrives as a QR code instead of a piece of plastic. You buy it online before you leave home, scan the code, and your phone downloads the profile. There is nothing to collect at the airport, nothing to post back, and no tiny tray to lever open with a paperclip at midnight.
The quiet advantage is dual SIM. Your home number stays active on your normal line for calls and verification texts, while the Japanese eSIM handles data. If your bank sends a code to your home number mid-trip, you still get it.
First, check your phone supports it
Open your dialler and enter *#06#. If an EID appears in the list — a long 32-digit number, sometimes labelled “EID 2” and sometimes buried at the bottom of the screen — your phone supports eSIM. No EID means no eSIM, and you want a prepaid SIM or pocket WiFi instead. Broadly, iPhones from the XS and XR onwards, recent Google Pixels and most flagship Samsung Galaxy models are fine, but check rather than assume: the same model bought in different markets can differ.
CDJapan Rental eSIM plans
CDJapan Rental’s eSIM runs on the docomo network, which has the broadest coverage in Japan — the difference shows up when you leave the big cities for the mountains or the coast.
| Plan | Data | Price |
|---|---|---|
| 8 days | 30 GB | ¥3,200 |
| 16 days | 50 GB | ¥3,900 |
| 31 days | 50 GB | ¥4,900 |
| 91 days | 135 GB | ¥10,800 |
| 5 days | Unlimited | ¥2,800 |
| 10 days | Unlimited | ¥5,000 |
| 15 days | Unlimited | ¥6,300 |
| 31 days | Unlimited | ¥7,900 |
Fixed-data plans drop to 200 kbps once you pass the cap. Unlimited plans carry a fair usage policy: go past 3 GB in a single day and speeds are limited for the rest of that day, then reset the next morning. Prices as listed by CDJapan Rental at the time of writing — check the plan page for current rates.
Three things to know after you buy
A deleted eSIM cannot be recovered or reissued — you would have to buy a new one. If you need to fall back to WiFi or your home line for a while, disable the eSIM in your settings rather than removing it.
Installing the profile over your home WiFi is the sensible move, because airport WiFi is exactly where you don’t want to be troubleshooting. But the validity period starts when the plan is activated, so leave the line switched on until you’re in Japan. Watch the expiry date on the plan itself as well — it can’t be extended.
Cancel before activation and you can be refunded. After activation there is no refund — even if the phone then turns out to be incompatible, because the profile can’t be reissued for someone else. This is the single best reason to run the *#06# check before you pay.
One QR code installs on one device, once. Buying for two people means two separate orders, and an eSIM already installed on one phone can’t be moved to another.
Comparing eSIM providers
Plenty of companies sell Japan eSIMs and pricing changes often enough that any table of numbers goes stale within months. What doesn’t change is what’s worth comparing, so use these four questions on whichever provider you’re looking at.
| What to check | Why it matters |
|---|---|
| Which network it uses | docomo has the widest rural coverage; SoftBank and KDDI/au are strong in cities. Resellers rarely say this loudly — look for it. |
| What “unlimited” actually means | Almost every unlimited plan throttles after a daily threshold — the fair usage policy is where the real limits live. Compare the threshold and the throttled speed, not the word. |
| Speed after the cap | 200 kbps still runs maps and messaging. 128 kbps is close to unusable. This is a bigger practical difference than a few hundred yen. |
| Where support is based | A provider operating inside Japan can help you at Japanese hours while you’re standing in a Japanese station. Overseas resellers often can’t. |
Names you’ll come across include Sakura Mobile, Mobal, Japan Wireless, Nippon SIM and b-mobile, alongside international marketplace sellers. Run the same four checks across all of them.
Prepaid SIM cards: still the answer for some phones
A physical prepaid SIM is the older path and remains the right one if your phone has no eSIM support. You buy online before the trip, collect the card in Japan, swap it into your phone and you’re online. CDJapan Rental’s unlimited prepaid SIM starts at ¥3,900 and also runs on docomo.
Two compatibility questions decide whether this works, and they’re separate. First, is your phone unlocked? Carrier-locked handsets will reject a Japanese SIM outright. Second, does it support Japanese frequency bands? This is the one people miss — a phone can accept the card, complete the setup and still fail to connect, because the hardware doesn’t cover the bands the network uses here. We have separate walkthroughs for checking an iPhone and an Android phone before you commit. Some providers, CDJapan Rental included, offer insurance for exactly this scenario.
Swapping cards doesn’t wipe your phone. Photos, contacts and apps stay where they are. What changes is your phone number, so anything tied to it — two-factor codes, some messaging apps — may behave differently until you swap back. Put the original SIM somewhere you’ll definitely find it again; losing it during the trip is one of the most common and most annoying travel mishaps.
Getting the card into your hands
Most providers ship to the airport post office rather than a counter: order before you fly, then collect the package with your passport after baggage claim. The name on your order must match the name in your passport, because that’s what postal staff check. Full pickup details for each airport are in our airport WiFi and SIM pickup guide.
The thing nobody tells you about airport post offices is that they keep office hours. Narita’s are open 8:30 to 20:00, Haneda’s is in the domestic terminal and weekdays only, and Chubu Centrair’s is weekdays only too. Land at nine on a Sunday evening and the shutter is down — your data plan is sitting behind it until the morning.
And one airport has no post office at all: Kansai International Airport lost its branch in March 2021 and hasn’t replaced it.
If you order from CDJapan Rental, Kansai has a better answer than a post office. Your SIM card or pocket WiFi can be sent to a partner pickup counter on the 1st floor of KIX Terminal 1, open 7:00 to 21:00, every day of the year — no closing days, and late enough for most evening arrivals. Collection works exactly like a post office: give the tracking or order number, show your passport, done. The same arrangement covers Fukuoka Airport, on the 1st floor of the International Passenger Terminal, also 7:00 to 21:00 daily.
If your flight lands later than that, or you’d rather not carry it through the airport at all, hotel delivery works well — just make sure the recipient name matches your hotel booking name, and tell the front desk a package is coming. A hold at a post office in the city is the other option; we cover which branches are convenient in our guide to poste restante pickup in Osaka, along with the general mechanics of collecting mail at a Japanese post office if the system is new to you. Post offices hold packages for three to five days, so a delayed flight isn’t a disaster.
Pocket WiFi: the group and long-stay answer
A pocket WiFi is a rented portable router with its own SIM inside. You turn it on, join the network from your phone, and that’s the whole setup. It’s the only option on this page with no compatibility question attached — if a device can join a WiFi network, it works, including laptops, tablets and the older phone your parent is travelling with.
For three or more people the maths usually wins outright: one rental covers roughly ten devices at once, against three or four separate data plans. CDJapan Rental’s short-term rentals are priced by the day across SoftBank 100GB, SoftBank Unlimited and WiMAX+5G Unlimited plans, and the daily rate falls as the rental gets longer — check your dates on the plan page for the exact figure.
The costs are real, though, and worth naming. It’s another object to carry and another thing to charge — expect somewhere around eight hours of battery, so a power bank is sensible on long days. Leave it in the hotel and your phone is offline until you get back. And it has to be returned.
Returning it is easier than most people expect
The package includes a prepaid, pre-addressed envelope. Pack the router and cable, seal it, and drop it in any postbox in Japan by 11:59 PM on the last day of your rental. No counter, no queue, no return fee, and no requirement to return it where you picked it up — collect at Narita and post it near your Osaka hotel if that’s how the trip runs. Just post it before you go through airport security, not after. If you’d rather use an airport postbox, our guide to WiFi return postbox locations shows exactly where they are.
Ordering notes. Shipping is a flat ¥690 per order. Book at least a week ahead where you can — reservations are accepted up to three days before your start date, and you can still order once you’re in Japan for delivery to your accommodation. Deliveries can’t be made to Airbnb addresses, so contact the shop to arrange another pickup point. Cancel five or more days before the start date for a full refund; later cancellations are partial.
Long stays, remote work and months rather than weeks
If you’re here for a semester, a work posting or an extended remote-working stint, the short-term products stop making sense and the monthly ones take over. Unlimited monthly routers start at ¥5,500 a month on either WiMAX+5G or SoftBank, with a 100GB SoftBank plan at ¥4,600; longer contracts bring the monthly rate down — we broke down how the monthly subscription plan works when it launched. This is the practical choice for anyone who needs a connection that holds up for video calls all day and doesn’t want to sign a two-year contract with a Japanese carrier — see the long-term WiFi plans for the full range.
Roaming and free WiFi: the two backups
Roaming is the least effort and the most money. Switch it on before you fly and you’re connected the moment you land, with no orders, no pickups and no setup — which is genuinely worth something on a two-night trip. But daily unlimited roaming passes typically run ¥1,000–2,000 a day, and most cap high-speed data at a couple of GB before throttling. A fortnight of roaming can cost several times a month of local data. Treat it as a bridge for the first few hours if you want, not as the plan.
Free public WiFi exists in cafés, convenience stores, stations, department stores and on some Shinkansen, and it’s a reasonable backup. As a primary plan it fails in ordinary ways: it isn’t where you need it, it’s slow when the café is full, sessions frequently drop after thirty minutes and make you log in again, and registration often wants an email address — which you need internet to reach. It’s also open by definition, so it isn’t the place to enter card or account details. Our guide to finding free WiFi in Japan covers where it’s genuinely reliable.
Can you make calls or send texts?
Almost certainly not on a tourist data plan, and this catches people out. Japanese regulations require identity verification for a voice-capable line — a residence card and a Japanese address — so short-term visitors can’t buy one. Data SIMs and eSIMs sold to travellers are data only: no phone number, no calls, no SMS.
For talking to people this barely matters. LINE is the default in Japan and everyone here has it; WhatsApp and Skype work fine over data too, for voice and video alike. Where it does matter is SMS verification — the codes some banks, apps and booking sites insist on sending by text. If you rely on those, or you’re staying long enough to need a Japanese number for sign-ups, CDJapan Rental’s SMS-capable SIM is a monthly docomo plan with 25 GB and SMS from ¥4,400.
Keeping your home SIM active alongside a Japanese eSIM sidesteps the whole problem: your usual number still receives verification texts, while data runs over the local line. Just check what your home carrier charges to receive an SMS abroad before you rely on it.
Japan is where you’ll want data at the least convenient moments — reading a platform sign in Kanazawa, finding the right exit at Shinjuku, translating a menu with no pictures. CDJapan Rental’s eSIM runs on the docomo network for coverage that holds up well outside the big cities, and there’s nothing to collect or post back: buy online, scan the QR code, and you’re online the moment you land.
The rest of your pre-flight admin
Data is one of three things worth settling before you fly. The other two are Visit Japan Web, which turns your immigration and customs paperwork into a QR code, and a transport IC card — our Welcome Suica guide covers the tourist version and where it’s currently sold. Japan is also more cash-dependent than most visitors expect, and how much cash to bring is worth ten minutes of thought before you’re standing at a ticket machine.
Frequently asked questions
Pocket WiFi or eSIM — which is better in Japan?
It depends on how many of you there are. Travelling alone or as a couple, an eSIM is cheaper and simpler, with nothing to collect or return. For three or more people, or if you’re bringing laptops, a single pocket WiFi covers about ten devices and works out cheaper than separate plans. Pocket WiFi is also the safe choice if your phone doesn’t support eSIM or you’re unsure about band compatibility.
Will my phone work with a Japanese SIM or eSIM?
Three conditions have to hold. Your phone must be carrier-unlocked; for eSIM it must have an EID, which you can check by dialling *#06#; and for any SIM it must support Japanese frequency bands. That last one is the common failure — a phone can complete the setup perfectly and still not connect. If any of the three is in doubt, rent a pocket WiFi instead, since it has no compatibility requirements at all.
Can I make calls or send SMS with a Japanese data SIM?
No. Voice and SMS lines in Japan require identity verification with a residence card and Japanese address, so tourist plans are data only. Use LINE, WhatsApp or Skype for calls and messages. If you specifically need SMS verification codes, look for a SIM that lists SMS support, or keep your home SIM active alongside a Japanese eSIM.
How much data do I need for a week in Japan?
For maps, messaging, searching and some photo sharing, roughly 5–10 GB covers a week comfortably. Add daily video calls or streaming and 20–30 GB is more realistic. Turning off automatic photo backup and downloading offline maps before you travel cuts usage considerably.
Is “unlimited” data in Japan really unlimited?
Mostly, but with a fair usage policy attached. Providers throttle speeds once you pass a daily threshold — with CDJapan Rental’s unlimited eSIM that’s 3 GB in a day, after which speeds are limited until the following morning. When comparing plans, compare the daily threshold and the throttled speed rather than the word “unlimited”.
Can I get a refund on an eSIM?
Before activation, yes. After activation, no — including cases where the device turns out to be incompatible, because an activated profile can’t be reissued. Deleting an installed eSIM also forfeits it with no reissue or refund. Check compatibility before you pay, and disable rather than delete if you need to switch lines mid-trip.
Where do I pick up a SIM card or pocket WiFi?
Most providers deliver to an airport post office for pickup with your passport, or ship to your hotel. Watch the opening hours: airport post offices close at 20:00 or earlier, and some open on weekdays only. Kansai International Airport has had no post office at all since March 2021 — CDJapan Rental orders can instead go to a partner counter on the 1st floor of KIX Terminal 1, open 7:00 to 21:00 every day, with the same arrangement at Fukuoka Airport. Airport-by-airport detail is in our airport WiFi and SIM pickup guide.
Is free public WiFi enough on its own?
Not for a trip you want to enjoy. It’s genuinely useful as a backup in cafés, convenience stores and stations, but coverage is patchy, speeds drop when it’s busy, sessions time out, and registration usually needs an email address you can’t reach without a connection. Treat it as a supplement to a paid plan rather than a replacement.
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Short trip or long stay — we've got you covered
Best for Travelers
Japan eSIM
From ¥2,800 — activate before you land
- Cheaper than airport & convenience store SIMs
- 5-day to 135-day plans; unlimited or data-capped
- No SIM swap needed — ready in 2 minutes
Best for Long Stays
Monthly Pocket WiFi
From ¥5,500/mo — unlimited, no throttle
- Choose WiMAX 5G or SoftBank 4G coverage
- 3 to 12-month contracts — longer means cheaper
- Delivered to your hotel or airport post office
