Japan SIM Card: Choose a Travel Data Plan

JGO! editorial team — WEBMARKS Inc. (Fujisawa, Kanagawa)

Before buying a Japan SIM card, check that your phone is unlocked, supports the relevant network and can use the SIM format you plan to buy. Compare the allowance and validity period alongside the price, delivery method and start date: a low product price may not include shipping, and the plan may start counting before you first connect. The examples below are data-only travel products, not conventional Japanese phone-number plans.

The prices and conditions in this guide were checked on November 3, 2026, unless otherwise stated. Provider terms can change, so confirm the product details on the official page before paying. In particular, verify the exact plan, delivery option, supported device and usage-period rule on your order.

1. Compare Japan SIM card examples

These examples differ in how they measure data: b-mobile sets a total allowance for the plan, while Sakura Mobile lists a daily allowance for one product and an unlimited plan with a tethering limit for its seven-day SIM. Their coverage networks and plan conditions also differ, so “more data” is not the only useful comparison. Sakura Mobile’s physical-SIM price was not established in the available information; confirm it with the provider rather than estimating it.

The b-mobile product prices do not include the separate delivery charge, which is shown as ¥600 or ¥430 depending on the selected destination option. Both b-mobile plans end when either the allowance is used or the stated validity period ends, whichever happens first; a large remaining allowance does not extend the plan past its time limit. See the provider’s VISITOR SIM plan details and check the specific delivery option before ordering.

Sakura Mobile’s 3 GB/day plan works differently from a plan with a fixed total allowance: according to the provider, reaching 3 GB in one day results in a 1 Mbps speed limit rather than disconnection. The listed seven-day unlimited SIM has a tethering limit of up to 6 GB, so “unlimited” should not be read as unlimited tethering. Sakura Mobile’s travel-plan page lists plan details, but the physical-SIM price was not confirmed in the information available for this guide.

Treat these as comparisons of listed product conditions, not as a complete ranking for every trip. For example, a traveller who needs a fixed amount of data for a shorter stay may prefer to compare the b-mobile allowance and validity together, while someone who expects heavy daily use may want to examine Sakura Mobile’s daily speed-limit rule. None of the listed products supplies a conventional telephone number, so do not choose one on the assumption that it includes normal voice calling.

2. Check your phone before you buy

Confirm three separate things before purchasing: the phone must be unlocked, it must support the relevant network, and it must accept the SIM format. b-mobile lists an unlocked device, LTE capability and suitability for safe use in Japan among its requirements. Sakura Mobile also says its travel SIM and eSIM require an unlocked device; its compatibility guidance is the place to check its requirements for a particular device.

On an iPhone, open Settings → General → About and find Carrier Lock. Apple says that “No SIM restrictions” means the iPhone is unlocked; if the phone is locked, only its current carrier can unlock it, not Apple. Check the result before ordering rather than assuming that a phone bought overseas is ready to use in Japan. Apple explains the check and who can unlock a device in its iPhone carrier-unlock guidance.

An unlocked phone may still lack a physical SIM slot. Apple lists US-purchased iPhone 14, 15 and 16 series as eSIM-only, and also lists iPhone 17, 17e, 17 Pro and 17 Pro Max purchased in specified regions, including the US and Japan, as eSIM-only. The exact model and purchase region matter; check Apple’s SIM-type information rather than relying on the model name alone. Apple lists the iPhone 13 series as supporting nano-SIM, but that does not remove the need to check the exact model and region.

The b-mobile physical SIM is a multi-cut card that supports standard, micro and nano sizes. Do not cut or modify a SIM to make it fit: Apple cautions that doing so can prevent connectivity or disable some functions. Use the size and installation method intended for your phone, and follow the supplier’s instructions for any setup steps. If the device or plan needs configuration that is not covered by the product information, ask the provider rather than guessing at network settings.

3. Understand coverage, data limits and calling

b-mobile says VISITOR SIM uses NTT Docomo’s network, supports tethering subject to device compatibility and is intended for use in Japan only. It does not support international roaming. Its FAQ also says SMS and MMS are unavailable, although internet-based VoIP calls are possible; this is different from a plan that provides a normal Japanese telephone number. Check the b-mobile FAQ if you need to confirm what the data-only product can and cannot do.

Sakura Mobile lists different networks and 4G bands for its two travel SIM examples. Its Docomo-network 3 GB/day SIM lists Band 1 as a main band and Band 19 as a supplementary band, while the au-network unlimited SIM lists Band 1 as a main band and Band 18 as supplementary bands. Check the supported bands for your exact phone and plan against Sakura Mobile’s device compatibility information; a phone being unlocked does not by itself establish that it supports the bands listed for a product.

Sakura Mobile specifically recommends pocket Wi-Fi to travellers mainly visiting rural or mountain areas if their Docomo-network device supports Band 1 but not Band 19. That is a provider recommendation tied to that stated combination of travel area and device bands, not a guarantee of performance in every location. If your itinerary includes rural or mountain areas, compare the device’s supported bands and the provider’s network details before relying on a SIM as your only connection.

Pay attention to the difference between a daily speed limit and a total plan limit. On Sakura Mobile’s 3 GB/day SIM, the provider says service continues at 1 Mbps after 3 GB of use in a day; by contrast, the b-mobile plans end when the total allowance or validity period is reached, whichever occurs first. Check the conditions for the exact product you select, including its tethering limit, rather than applying one plan’s rule to another.

4. Plan delivery and the start of service

b-mobile lists delivery of its physical SIM to an airport post office or to a hotel, home or office. The listed delivery charges are ¥600 or ¥430 depending on the destination option, and those charges are separate from the 5 GB and 7 GB product prices. The provider lists airport post-office delivery for Narita, Haneda, New Chitose and Chubu Centrair; confirm that the option is available for your order and travel dates on the official plan page.

The start-date rule depends on where you receive the parcel. For airport post-office collection, the usage-period count begins automatically on the day after the designated pickup date, whether or not that matches your first day of internet use. A passport is required for collection, and if you do not pick up the parcel, the post office holds it for seven days from the designated date but does not forward it to another address.

Hotel, home and office delivery use a different start rule: the usage-period count begins on the day after you first use the internet. b-mobile also says use must begin by the end of the month following the shipping month. These rules make delivery destination a practical part of plan selection, especially if you intend to receive the SIM before travelling or will not connect immediately after delivery. Confirm the precise shipping and activation terms shown for your order before paying.

For airport collection, compare the designated pickup date with your arrival and the post office’s collection arrangements before choosing the option. The provider’s seven-day holding period does not mean a missed parcel can be sent to your hotel or another airport. For hotel or home delivery, note the latest permitted start date as well as the later count-start rule; do not assume the plan begins on the day the parcel arrives.

5. Top up or buy a SIM at Narita Airport

b-mobile lists an additional charge of ¥500 including tax for 1 GB and one day. It can be paid for by credit or debit card and must be made in Japan no later than two days after the usage end date. The provider’s top-up page gives the terms, while its FAQ says the status page shows remaining data and the usage end date.

The result of a top-up depends on the plan’s status. If both data and time remain, the provider says the top-up adds 1 GB to the remaining allowance and extends the usage period by one day. If the usage period has expired and the allowance is also exhausted, the top-up provides 1 GB until 23:59 that day; check the status page and the provider’s instructions before paying so you know which case applies.

Narita Airport lists GPA SIM-card vending machines in Terminal 1’s central building, Terminal 2’s main building and Terminal 3’s main building. GPA says its Narita machines are available 24 hours, asks customers to check that their phone is unlocked before purchase and does not refund purchases for customer convenience. See the airport’s internet-service information and GPA’s SIM vending-machine details before relying on an airport purchase.

There is a discrepancy in Narita’s location information: a general note says SIM sales locations are limited to areas before departure procedures, while the Terminal 2 listing also identifies a machine on the second floor before immigration procedures. Confirm the current location and whether it is accessible for your journey directly with the airport before depending on that specific listing. Since GPA says it does not refund purchases for customer convenience, check phone compatibility and the exact product before buying from a machine.

6. Frequently asked questions about Japan SIM cards

Does a b-mobile VISITOR SIM include a Japanese phone number?

No. b-mobile describes VISITOR SIM as a data-only product and says it does not provide normal telephone service or SMS/MMS. Its FAQ says internet-based VoIP calls are possible, but that is not the same as receiving a conventional phone number. If a particular service requires a phone number or SMS, check that requirement before choosing this plan.

Can I use a physical SIM in an eSIM-only iPhone?

No. A phone without a physical SIM slot cannot use a physical SIM card, even if the card’s size would otherwise match. Apple lists certain iPhone models as eSIM-only depending on model and purchase region, so check the exact device against its SIM-type guide. Do not infer the SIM format from the model name alone.

When does the b-mobile usage period start?

For airport post-office collection, the count starts automatically on the day after the designated pickup date, and a passport is required to collect the parcel. For hotel, home or office delivery, the count starts the day after the first internet use, but use must begin by the end of the month following the shipping month. These are different rules, so confirm the selected delivery method and order terms before purchase.

Can I cancel or get a refund after buying?

b-mobile’s purchase notes say cancellation and refunds are unavailable after purchase completion. GPA likewise says it does not refund a vending-machine purchase for customer convenience. Read the current terms and check the phone, plan and pickup details before completing a purchase, particularly when buying at an airport.

What if my phone is locked?

Ask the phone’s current carrier whether it can unlock the device; Apple says it cannot unlock a carrier-locked iPhone itself. Sakura Mobile identifies pocket Wi-Fi as an alternative for a Wi-Fi-capable device that cannot be unlocked. Check the rental product’s conditions and availability before relying on it, since the supplied information does not establish availability for every device or trip.

Can I top up b-mobile after the plan ends?

A top-up costs ¥500 including tax for 1 GB and one day, and the provider says it must be made in Japan no later than two days after the usage end date. If both data and time remain, the extra data is added and the period extends by one day; if both the period has expired and the allowance is exhausted, the 1 GB lasts only until 23:59 that day. Check the status page for the remaining allowance and end date, then confirm which rule applies on the official top-up page.

7. Videos about Japan travel data

Travel videos can help illustrate the differences between SIM cards, eSIMs and pocket Wi-Fi, but each covers particular products and a particular point in time. The plan details in a video may not match the product currently offered or the conditions for your phone. Confirm compatibility, price, delivery and validity with the provider before buying.

The existing video recommendations include Tokyo Cheapo’s comparison of Japan SIM cards for travellers and Kensho Quest’s comparison of pocket Wi-Fi, eSIM and SIM cards. Other listed videos are Kyonversation’s 2026 Japan SIM-card travel video and Shahin From Japan’s prepaid SIM-card comparison. Japan Linked has a video about buying SIM cards at Japanese airports, while WOW THAT’S JAPAN 2 has a video about a prepaid eSIM for travellers; check the video date and the provider’s current terms before acting on product advice.