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公開2025.01.03更新2025.01.03

Smartphone settings and precautions you need to take when traveling abroad

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To use my phone/mobile phone abroad, I asked, "Are there any settings I need to do if I'm going abroad?" I want to use my phone when I travel abroad. What settings do I need to make?" We will introduce the best way to use your smartphone overseas, answering questions such as these.

Table of Contents

eSIM is recommended to use your smartphone when traveling abroad!

The long-awaited trip abroad! You have made arrangements for your airline tickets and hotel, prepared your passport and personal belongings, and researched the places you want to visit, and all you have to do is go to the airport! But the last thing you should not forget is to prepare your smartphone. Traveling abroad is an exciting time for many people, but it requires a little planning when it comes to using your smartphone. If you use your phone in the same way as you would in Japan without planning ahead, you may end up with an outrageous bill later on.... It is important to think carefully about how to connect to the Internet in advance according to your needs, such as the number of days you will be traveling, the devices you will use, and the number of people you will be traveling with. In addition to rental Wi-Fi and SIM cards, eSIMs have recently been introduced to connect to the Internet locally. Their use is increasing every year, and they are revolutionizing the use of smartphones when traveling abroad.

Why can't I use my smartphone abroad?

If you try to use your phone as-is abroad, you may face several problems. Please find out what kind of problems can occur and research carefully beforehand what the status of the device you are going to use is, what the contract with the smartphone carrier is currently like, and whether there are any plans that offer good deals when you go abroad.

Functions that cannot be used overseas and the reasons why

Network compatibilityIn some countries, the band of the smartphone you are using may not be compatible with the local network. In such cases, even if you have gone to the trouble of bringing it with you, you will not be able to use it and will have problems during your trip. Also, if you are traveling alone, you will not be able to contact them in case of an emergency, so be sure to do your research.
SIM lockIf you use your phone in a country other than the one where you purchased it, you will not be able to use a SIM card from another network if it is SIM-locked. Even if you prepare an overseas SIM card in Japan in advance and bring it with you, it may not work even if you bring a local SIM card overseas and replace it. It is important to check whether your phone is SIM-free or not. You should also be careful about a phone you bought used.

Can I use it if I am in an area covered by international data roaming?

International data roaming is a method of connecting to the Internet overseas using the same telecommunications carrier you have a contract with in Japan. By using international data roaming, you can use your smartphone overseas in many cases. In most cases, you only need to operate a switch on your smartphone's settings screen to use the service, making it easy and convenient. However, it still needs to be confirmed before departure, as it depends on the area covered and the plan.

International data roaming can be expensive!

International data roaming is convenient because it is easy to use and you do not need to carry other devices such as rental Wi-Fi with you, but if you use it without planning, you may be charged a very high fee. There are various plans for international roaming offered by telecommunication carriers, including pay-as-you-go, flat-rate, and pre-paid plans. In the case of pay-as-you-go plans, the more you use, the more you are charged, and the more you use, the more you are charged. In the case of pay-as-you-go plans, the more you use, the more you are charged. For example, if you use a large amount of data in a short period of time without realizing that you are on a pay-as-you-go system, such as using LINE, making video calls, or walking around overseas using map applications all day long, it is not unusual to receive a bill ranging from several tens to several hundred thousand yen. If this is the case, I could have taken one more trip abroad..." If this is the case, I could have taken one more trip abroad..." Make sure to check the details carefully so that you will not be disappointed.

Six ways to use your smartphone overseas

There are several ways to use your smartphone to connect to the Internet overseas. You can rent a Wi-Fi rental in Japan, prepare a SIM card, use international roaming, or use an eSIM. Each of these methods has its own advantages and disadvantages, such as the convenience of traveling with multiple people, but also the hassle of contracting and returning the card, and the difficulty of setting up a smart phone, although it can be used smartly. The table below summarizes these advantages and disadvantages.

	eSIM	SIM Card	Free Wi-Fi	Rental Wi-Fi	nternational Roaming	Local Carrier
How to use	QR code online Read or enter code	Replace physical SIM card	Register on the website	Offline at the airport Receive	None	Sign up with local carrier Contracting with a local carrier
Fees and Charges	Cheap	Cheap	Free~Cheap	Slightly expensive	Slightly expensive	Cheap
Security	Safe	Safe	Dangerous	Slightly Safe	Safe	Safe
Difficulty of setting	○	○	◎	◎	○	△
Difficulty of introduction	◎	△	◎	◎	◎	△
Convenience of service	◎	○	△	△	○	○

eSIM

Advantages of using eSIM

ImmediacyYou can purchase a data plan online and start using it as soon as you arrive at your destination. This is convenient for reporting your arrival to family in Japan as soon as you get off the plane, checking transportation from the airport to your hotel, or doing research while traveling from the airport.
ConvenienceNo hassle of replacing physical SIM cards. With a conventional SIM card, you must first purchase a SIM card, have it ready at hand, and then replace it before arriving overseas. This is not the case with SIM cards on airplanes, which often happen when the plane is shaking and the SIM card falls into the space between the seats, making it impossible to remove it. In addition, multiple plans can be stored and switched as needed. Demand for eSIMs has been increasing in recent years because they are more convenient than physical SIM cards.
Extensive compatibility eSIMs are widely supported by the latest smartphones. Most smartphones purchased within the last few years can be used. You do not need to prepare a special device and can use your regular smartphone as it is, so you can use the Internet during your trip stress-free and keep in touch and do research just as you would in Japan.

Disadvantages of using an eSIM

Compatibility IssuesNot all smartphones are compatible with eSIM. In particular, older models and some lower-priced models may not be compatible. If you go to a local market expecting to use an eSIM and find that it does not work, you will have to think about your next move abroad, which can be difficult. It is advisable to check the websites of each company in advance whether the eSIM of the company you are planning to use is compatible with the smartphone you plan to use overseas.
Limited availability of plans: In some regions, the eSIM data plans that are available may be limited. Check in advance whether and to what extent the eSIM plan you plan to use is available at your destination.

Settings and precautions when using an eSIM

Confirmation of compatibilityBefore traveling, you must confirm that your smartphone is eSIM compatible and that there is an eSIM provider available in your destination country. It is also necessary to check if the phone was purchased through second-hand sales, not through official channels, or if the phone was purchased overseas.
Selecting a PlanChoose the best plan for the amount of data you need and the length of your stay. Usually this is purchased through an app or website. Physical SIM cards require the hassle of applying online and waiting for the card to arrive, or going to the airport early to purchase, etc. The big advantage of eSIM is that everything can be completed online.
The setup procedure is done by scanning the QR code provided at the time of purchase or by manually entering the setup information to activate the card. This can be a little difficult for older people and others who are not used to operating a smartphone. Make sure you know how to use it so that you will not have problems when using it locally.

Persons for whom eSIM is recommended

Frequent international travelers, travelers visiting multiple countries, frequent international travelers, and international business travelers who find it a bit of a hassle to purchase a SIM card each time. eSIM saves you the trouble of having to purchase a local SIM card over and over.
For those who use the latest smartphones, eSIM is available for most people who use the latest devices. Completed online and with no hassle before or after your trip, an eSIM is a convenient and efficient option. In fact, more and more smartphone users, especially young people and business people, are using it.

SIM Cards

Advantages of using a SIM card

Extensive compatibility Physical SIM cards are available for most smartphones. It is not difficult to use by opening the case on the side of the phone and replacing it. It is convenient because you can use the same phone you normally use!
FlexibilityYou can purchase a SIM card in advance in Japan and bring it with you, or you can purchase a SIM card locally and start using it immediately. The ease of use is a big advantage, as you can easily replace the card with another one after use.

Disadvantages of using a SIM card

You will need to find, purchase, and exchange SIM cards whether you prepare in advance in Japan or purchase locally, and after replacing the SIM card, you will need to keep the SIM card you are using in Japan in a case for when you return home.
SIM lockSome phones are SIM-locked by the carrier and can only be used with a SIM card from a specific network. If you go abroad without knowing this, you will not be able to use the Internet even if you replace the SIM card. In addition, smartphones purchased through used sales are rarely known as "Red ROM. These Red ROM handsets have usage restrictions due to unpaid handset portions, etc., and cannot be used even if the SIM card is replaced. It is not obvious from the appearance, but it can be confirmed by the serial number, so take a look if you are concerned.

Settings and precautions when using a SIM card

Before traveling to unlock your SIM card, check to see if your smartphone is SIM-locked or needs to be unlocked. As an example, here is how to check your iPhone. The SIM unlocking procedure differs depending on the software version, but if you are using iOS 14 or later, go to "Settings" > "General" > "Information" and scroll down to the bottom to find the "SIM Lock" field. If the field is set to "SIM Lock", the SIM lock has been removed.
Check the size of the SIM card. If you purchase a SIM card without checking the size and it is the wrong size, you will waste money and will not be able to use the Internet overseas. You need to check if the SIM card is compatible with the model of smartphone you plan to use, and purchase the appropriate size SIM card.

People for whom SIM cards are recommended

Long-term residentsIf you plan to stay in the same country for a long period of time, a local SIM card will allow you to use telecommunication services for a longer period of time at a lower cost. Rental Wi-Fi, for example, can be quite expensive for a long period of time, so it is a good idea to compare plans and consider whether to use a SIM card for the length of your trip.

Free Wi-Fi

Advantages of using free Wi-Fi

Free Wi-Fi provided in public places, cafes, hotels, etc. is free of charge. No fees are charged. Many cafes, hotels, and public facilities in other countries offer free Wi-Fi, so finding a place like that and using the Internet is another option.
Easy to use Free Wi-Fi provided in public places, cafes, hotels, etc. is free of charge. There is no charge at all. Free Wi-Fi is provided in many cafes, hotels, and public facilities overseas, so finding such places to use the Internet is one way to use the Internet.

Disadvantages of Using Free Wi-Fi

Security RiskWhile public Wi-Fi is easy for anyone to use, security is low. There is a risk that your history of what pages you have viewed can be viewed and that your personal information can be stolen. Be careful with devices you use for work or with credit card information on them.
Connection qualityFree Wi-Fi is easy to use, but the speed can be slow during busy times, and the connection may be unstable. Also, if many people are using it at once, you may not be able to connect no matter how long you wait. It is not suitable for important communications, exchanging heavy data, or using it for long periods of time.

Settings and Precautions for Using Free Wi-Fi

Use of a VPNWhen using free Wi-Fi, it is recommended to use a VPN, which restricts access from other parties, making it safer than using it as is. Whenever you use free Wi-Fi, use a VPN at the same time to encrypt your communications.
Usage RestrictionsSome Wi-Fi may have time or data restrictions. In many cases, the connection is lost after about an hour of being connected, and you have to reconnect again. Check the conditions of use in advance so that you do not have to worry about losing the connection at an important time.

People for whom free Wi-Fi is recommended

Short-stay visitorsFree Wi-Fi is a convenient option for travelers who are visiting for sightseeing or on a short business trip and have low data usage. If you just want to use the Internet in the morning or at night at your hotel, or use it quickly at cafes and other key locations, free Wi-Fi will do the job.

Rental Wi-Fi

Advantages of using rental Wi-Fi

Generally, a stable Internet connection is available due to the use of a dedicated device with a stable connection. If you are working abroad or going to an online meeting, you can rest assured that you will have a stable connection if you have one device.
Multiple Device ConnectivityWith a single Wi-Fi rental, you can connect multiple smartphones and tablets as long as you enter their passwords. This is convenient if you are taking multiple devices with you or if you are traveling with multiple people, as you can share the same device.

Disadvantages of using rental Wi-Fi

CostDaily rental fees are incurred. It is not so expensive for a short period of time, but the cost may be higher for a longer period of time. You need to compare the number of travel days and plans to get the best deal.
You will need to carry your portable rental Wi-Fi device with you at all times. This is not ideal for those who want to enjoy outdoor activities overseas or for those who want to travel light. If you lose the device, you will have to pay for it, so you also need to be careful about how you store it.

Settings and Precautions for Using Rental Wi-Fi

Book a rental Wi-Fi prior to your trip and pick it up upon arrival at the airport or have it delivered to your home in advance. This can take a little time, so you must plan ahead and be prepared.
Battery LifeIt is important to check the battery life of your device and bring a spare battery if necessary. In addition to charging your phone, you must also manage the charge of your Wi-Fi, or you may not be able to use the Internet due to lack of charge even if you have taken the time to bring it with you.

Who is recommended to rent Wi-Fi?

Group travelersAs mentioned above, this is useful when traveling with family or friends and want to share the Internet with more than one person. If you have a rental Wi-Fi, you don't need to prepare a SIM card for each person, just enter the password and everyone can use it.

Overseas Roaming

Advantages of using international roaming

ConvenienceYou can use your home phone number and plan abroad without changing SIM cards or preparing another device.
Immediate useNo special settings or contract changes are required, and you can start using your phone immediately after arriving overseas with simple operations on your smartphone's settings screen. This is also convenient when you want to contact Japan immediately after arriving at the airport.

Disadvantages of using overseas roaming

High feesData usage fees can be very high. There are a variety of plans available from each carrier for overseas roaming, but if you use the same data as you do in Japan while abroad, you may end up paying more and more money, and in many cases, you may be charged several hundred thousand yen.

Settings and Points to Note When Using Overseas Roaming

Check your carrier's overseas roaming plan before you travel, and change to the most appropriate option if necessary. Choose a flat-rate plan instead of a pay-as-you-go system, or a prepaid plan that allows you to use only what you have paid for. Checking your plan in advance is essential if you intend to use overseas roaming.

People for whom overseas roaming is recommended

Short-term travelersSuitable for short-term overseas stays limited to emergency calls and small amounts of data use. You can set up your phone so that it is normally disconnected, and only connect when necessary.

Contracting with a Local Carrier

Advantages of contracting with a local carrier

You can use a local rate plan that is suitable for low-cost, long-term stays. This is a highly recommended option for those who are staying for a long period of time, as it allows you to use the Internet economically and travel with peace of mind.
Local ServiceThe great advantage is that you can receive services and support provided by local carriers. If a problem arises, you can consult with the local carrier immediately.

Disadvantages of contracting with a local carrier

Complexity of the procedure: ID is required to sign a contract, and there may be a language barrier. Even when signing a contract in Japan, cell phone plans can be complicated, and it is even more difficult to understand them when they are in a foreign language.

Setting up a contract with a local carrier and points to note

Required DocumentsYou will usually need to prepare the necessary documents for signing a contract, such as a passport and proof of address. Many people may feel it is risky to show proof of address and other important information to sign a contract overseas.
Selecting a PlanCompare plans from local carriers and choose the one that best suits your needs. For those who do not understand foreign languages, there are carriers that allow you to sign a contract in Japan in advance, or there are services where an agent will come in and sign the contract on your behalf. Although there is a fee for this service, it may not be that expensive if you consider it as a peace of mind fee.

People for whom a contract with a local carrier is recommended

Long-term residentsThis is best for those who plan to stay in Japan for several months or longer and plan to use a lot of data and make a lot of calls locally. You will have access to local support and services, so it is easy to consult and solve problems such as communication problems in a timely manner.

Conclusion

eSIM is the best choice for individuals who are planning to stay in Japan for a short period of time. eSIM is easy, cheap, secure, and has fast connection speeds. eSIM saves you time and effort when you are in the country, and allows you to enjoy your trip more. It can be used as soon as you arrive, there is no need to worry about losing or returning it, and the price is relatively low, making it a one-stop solution for those who have an eSIM compatible device.

The eSIM application "trifa" can be used easily and securely in 3 minutes, even from the local area!

trifa" is an app that allows you to easily set up your eSIM and fulfill your overseas data communication needs safely and quickly. It is a must-have for international travel, as you can start using it immediately before your departure or even after you arrive there. There is no need to carry another device with you, and there is no hassle of replacing or returning it. Demand for this service is increasing every year, and the number of people using this service is expected to increase in the future.