Mobile data in Tokyo for a 3–7 day business trip: eSIM, pocket Wi-Fi or SIM card?

This article contains affiliate links. Prices and conditions were checked on each provider's official site between 15 and 19 October 2026.

The short answer: for a 3–7 day business trip to Tokyo, an eSIM installed before you fly covers getting around and staying in touch, and hotel or venue Wi-Fi covers anything heavy. Keep tethering to the minimum (looking things up, answering email on a laptop). Only if you must have a laptop online away from Wi-Fi, rent pocket Wi-Fi.

eSIM, pocket Wi-Fi or a physical SIM: which should I get?

For 3–7 days, one person and mostly phone use, buy an eSIM before you leave home. If you will keep a laptop on a mobile connection all day at the venue, need several devices online, or carry a company phone that will not accept an eSIM, rent pocket Wi-Fi. Choose a physical SIM only if your phone cannot use an eSIM.

The reasoning is simple. An eSIM is installed on your phone before the flight, so you land with data working and there is nothing to collect or return. Pocket Wi-Fi is a small battery router: pickup and return take effort, but it connects a laptop and a phone at once and does not depend on what your phone allows. A physical SIM means swapping cards in an unlocked phone, the least convenient option for a short trip.

One pick per type:

• eSIM: Airalo Japan. For a solo traveler who mainly uses a phone. Unlimited data at US$11.50 for 3 days, US$17.00 for 5, US$26.50 for 7, US$48.00 for 15. “Unlimited” comes with a fair-use condition: 3 GB a day at high speed (20 Mbps), reduced speed for the rest of that day (from Airalo’s own description of its Unlimited packages). See Airalo Japan plans →
• Pocket Wi-Fi: NINJA WiFi. For anyone who needs a laptop online away from Wi-Fi or has more than one device. 4G from 440 yen/day (1 GB/day) up to unlimited at 1,980 yen/day; 5G 2,200 yen/day; two units 3,520 yen. Pick up at Haneda Terminals 2 and 3 or Narita Terminals 1–3; order by 16:00 the day before.
• Physical SIM: Sakura Mobile Travel SIM. For a phone that cannot take an eSIM. From 3,850 yen tax included, tethering allowed, airport pickup or delivery to your hotel, English support. See Sakura Mobile plans →

Prices are quoted in the currency each provider uses (US dollars for the eSIMs, yen for the Japanese rental and SIM services).

I need to stay in touch with HQ and send big files. Will an eSIM handle that?

For calls, chat and email, yes. For large files, plan on not using it: send those over hotel or venue Wi-Fi. That is the whole answer.

Think of the mobile line as the tool for maps, messaging and email on the move, and for looking things up at the venue. One eSIM does all of that without trouble, and answering email on a laptop over your phone’s hotspot is fine too. Video and large decks are different: whichever line you choose, they run into a daily cap quickly, so plan from the start to move them over Wi-Fi.

Tethering conditions differ by product (checked on each official site, 19 October 2026):

• Airalo Japan (Unlimited): tethering is allowed, and tethered data counts toward the 3 GB-a-day high-speed allowance. One 1 GB video upload uses a third of that day’s full-speed data. “Unlimited” eSIMs from any provider normally carry a daily cap like this, so read the tethering terms before you buy.
• NINJA WiFi (unlimited plan): connects a laptop directly, so this is the option if you truly need a laptop online away from Wi-Fi. Rental routers can still be subject to usage limits depending on how heavily you use them, so the rule stays the same: heavy transfers go over Wi-Fi.

For anything heavy, use your hotel room’s Wi-Fi or the venue’s Wi-Fi. Each of our venue guides lists the venue’s Wi-Fi as the venue itself describes it, and our hotel pages help you pick a hotel close to the venue.

Can I just buy it at Narita or Haneda when I land? What if I arrive late?

At Narita, yes: vending machines and rental counters in every terminal, in the arrivals area before security. At Haneda, Terminal 1 has vending machines and WiFiBOX lockers open 5:00–24:00. For Terminal 3 (international arrivals), check the airport’s rental page for your arrival time.

Buying on arrival works but is slower than it sounds: you queue after a long flight and set things up in the arrivals hall. If you land after midnight, do not count on a counter being open. Install an eSIM at home before you fly, so data works as soon as airplane mode goes off. If you prefer pocket Wi-Fi, reserve it and check the pickup hours for your terminal and arrival time.

Is my home carrier’s roaming good enough? Will a company phone take an eSIM?

Two checks cover most cases.

Check how your roaming is billed. A flat daily rate is acceptable for a three-day trip if you do not tether. Pay-per-megabyte roaming can turn ordinary use such as maps and email into a bill of several hundred dollars or more. Read your carrier’s roaming terms before you leave, not at the airport.

Check whether your phone will accept an eSIM. Carrier-locked phones and phones managed by a company can refuse a new eSIM profile. Check in the phone’s settings before departure. If the phone is locked or your IT department controls it, take pocket Wi-Fi and leave the phone’s own plan as it is.

Do I need a Japanese phone number?

For most business trips, no. The one exception is if you will be phoning or texting Japanese clients during the trip: then get a separate eSIM that comes with a Japanese number.

What works without a Japanese number (checked on the official sites, 19 October 2026)

• GO taxi app: accepts overseas mobile numbers for registration since November 2023, and overseas-issued credit cards. You only need to receive the SMS verification code.
• Suica: on iPhone, the “Welcome Suica Mobile” app issues a Suica with no membership or personal details, valid 180 days. No phone number involved.
• Hotels: they contact you on the overseas number you gave when booking. A Japanese number is almost never asked for.
• SMS verification in general: codes sent to your home number arrive as long as roaming for SMS stays on (some plans charge for received messages; check before you leave).

Data-only eSIMs (Airalo, and NINJA WiFi’s SIM and eSIM) come without a phone number. Japanese law requires identity verification for any line with a phone number; data-only service is what you can use without that step.

Emergency numbers (a data-only eSIM cannot place calls: use your home SIM on roaming, or the hotel phone)

• Police 110, Fire and ambulance 119
• Japan Visitor Hotline (Japan National Tourism Organization) 050-3816-2787: 24 hours, 365 days, in English, Chinese and Korean, for accidents, illness, disasters and general travel questions

If you do need a Japanese number

Neither Airalo nor NINJA WiFi, the two products we recommend above, offers a plan with a number. Two options that do:

• Sakura Mobile “Travel Voice + Data eSIM”: a Japanese phone number for stays of up to 90 days, 3 GB a day at high speed, 120–480 minutes of domestic calls included depending on the plan, incoming calls free, from 1,375 yen tax included. Because the law requires it, you complete an in-person ID check after arrival, at selected airport counters or the Shinjuku office, before the line starts; it cannot be activated before you land. See the Sakura Mobile Voice + Data eSIM →
• Mobal “Voice + Data SIM”: a 070/080/090 number, 4,950 yen for the SIM plus plans from 1,650 yen a month (1 GB). Passport ID check; pickup counters at Narita Terminals 1 and 2 and Haneda Terminal 3. Better suited to people who come to Japan month after month than to a single short trip.

Quick picks

• One person, phone only, 3–7 days: Airalo Japan eSIM, installed before departure.
• Large files: hotel or venue Wi-Fi. The mobile line is for getting around and staying in touch.
• Laptop online away from Wi-Fi, several devices, or a locked company phone: NINJA WiFi, reserved by 16:00 the day before.
• Arriving after midnight: install the eSIM before you fly.
• Phoning or texting Japanese clients: Sakura Mobile Voice + Data eSIM with a Japanese number (in-person ID check after arrival).

Sources (checked 15–19 October 2026)

• Airalo Japan eSIM, Airalo Unlimited packages (tethering, 3 GB/day), Airalo help: tethering
• NINJA WiFi
• Sakura Mobile Travel eSIM (Voice + Data), call and SMS rates
• Mobal Japan SIM Card
• GO app: overseas phone-number registration from 10 Nov 2023 (Impress Watch, Japanese), GO app registration steps (official support)
• JR East: Welcome Suica Mobile press release
• Japan Visitor Hotline (JNTO)
• Narita Airport: phone and Wi-Fi rental, Haneda Airport: phone rental

Change log: published 19 October 2026.