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Clay Thomas
Here’s the clean version with no UTM parameters anywhere and no changes to your sentences beyond adding internal links.
A physical SIM stores the information your phone needs to connect to a mobile network on a removable card. With an eSIM, that information is downloaded to a secure component already built into your phone.
When you add an eSIM, usually by scanning a QR code or using your carrier’s app, your phone downloads a mobile network profile and installs it on the device. Once the profile is enabled, your phone can use it to connect to the supported network just as it would with a physical SIM.
In this guide, we’ll explain what an eSIM is, what actually happens when you install one, how it connects your phone to a mobile network, and how it works alongside a physical SIM or other eSIM profiles.
What Is an eSIM?
An eSIM, short for embedded SIM, is a digital alternative to the physical SIM card you insert into your phone.
Instead of storing your mobile subscription on a removable plastic card, an eSIM-compatible phone has a secure component built into the device that can store downloadable carrier profiles.
Each profile contains the information your phone needs to identify your mobile subscription and connect to the carrier’s network.
Once an eSIM profile is installed, it works just like a physical SIM. Depending on the plan, you can use it for mobile data, calls, and text messages.
Many travel eSIMs are data-only, while eSIM plans from regular mobile carriers may include a phone number, calls, SMS, and data.
One advantage of this setup is that a phone can store more than one eSIM profile. You can switch between plans in your phone settings without removing or replacing a physical SIM card.
How Does an eSIM Work?
An eSIM works by downloading a mobile network profile to your phone instead of storing that information on a removable SIM card.
The process usually starts when you buy an eSIM plan or receive one from your carrier. The provider gives you a QR code, activation link, app-based setup, or manual installation details.
1. Your Phone Downloads the eSIM Profile
When you scan the QR code or start the setup through an app, your phone uses that information to securely retrieve the eSIM profile from the provider.
The QR code itself is not the eSIM. It gives your phone the information it needs to download the profile that is linked to your mobile plan.
Behind the scenes, this usually happens through a secure provisioning system that delivers the carrier profile to the eSIM component built into your phone.
2. The Profile Is Installed on Your Phone
Once the profile is downloaded, it appears as a mobile line in your phone settings.
You can usually name the line, turn it on or off, and choose whether to use it for mobile data, calls, or messages, depending on what the plan supports.
If your phone supports Dual SIM, you can also keep your existing SIM active at the same time.
3. Your Phone Connects to the Mobile Network
When the eSIM line is enabled and your phone is within the supported coverage area, the profile allows the device to authenticate with the mobile network.
From that point, the connection works much like it would with a physical SIM.
Your internet speed and coverage do not depend on whether you are using an eSIM or a physical SIM. They depend on the network, your plan, your location, network congestion, and your phone's capabilities.
eSIM vs Physical SIM: What’s the Difference?
An eSIM and a physical SIM identify your mobile subscription and allow your phone to connect to a carrier’s network.
The main difference between them is how your phone stores that subscription. A physical SIM uses a removable card that you insert into a SIM tray, while an eSIM stores the carrier profile digitally on a secure component built into the device.
With a physical SIM, changing carriers or plans may mean removing one card and inserting another. With an eSIM, you can usually add or switch between profiles through your phone settings without opening the SIM tray.
An eSIM can also make it easier to keep more than one mobile plan on the same phone. For example, you can keep your regular SIM active for calls and texts while using a travel eSIM for mobile data.
The network connection itself is not automatically faster or slower because you are using an eSIM. Speed and coverage still depend on the carrier, your plan, your location, network congestion, and the phone you are using.
Can You Use an eSIM and a Physical SIM at the Same Time?
Yes. Many phones that support eSIM also support Dual SIM, which means you can keep a physical SIM active while using an eSIM on the same device.
For example, you can keep your regular SIM active for calls, texts, and verification codes while using a travel eSIM for mobile data. In your phone settings, you can choose which line handles data and which line you want to use for calls or messages.
Some newer phones can also use two eSIMs at the same time without a physical SIM. The exact number of active lines depends on the phone model.
If you are using a travel eSIM, make sure it's selected as your mobile data line. You may also want to turn off data roaming on your home SIM so your phone does not accidentally use your regular carrier’s roaming data while you are abroad.
Can You Store More Than One eSIM?
Yes. Many eSIM-compatible phones can store several eSIM profiles at the same time, even if they can only keep one or two lines active.
This means you can keep different plans on your phone and switch between them in your mobile settings without reinstalling each one every time.
For example, you could keep your regular carrier eSIM, a Japan eSIM, and another travel profile stored on the same device.
The number of eSIM profiles you can store and use at the same time depends on the phone model. Some phones support multiple stored profiles but only one active eSIM, while newer models may allow two eSIM lines to stay active at the same time.
You can usually turn an unused eSIM off without deleting it. This is useful if you plan to use the same profile again later and the provider allows the plan or profile to be reused.
What Happens if You Delete or Change an eSIM?
If you turn the eSIM off in your phone settings, the profile stays installed on the device. You can usually turn it back on later without downloading it again.
If you delete the eSIM, the profile is removed from your phone. Whether you can reinstall it depends on the provider. Some carriers allow you to transfer or download the profile again, while others use activation details that cannot be reused.
The same applies when you move to a new phone. Some carriers support direct eSIM transfer between compatible devices, while others require you to request or install a new profile.
If you are using a travel eSIM, it is usually better to leave the profile installed until your trip is over. For Journey Japan eSIM, you can't currently reinstall or reissue a deleted eSIM.
Use a local Japan eSIM for Your Trip to Japan
If you are traveling to Japan, you can buy and install your eSIM before you leave so your mobile data is ready when you arrive.
Journey Japan eSIM offers fixed-data plans with 10GB, 20GB, and 50GB, along with True Unlimited options for travelers who expect to use more data. Depending on the plan, you connect through major Japanese networks such as NTT Docomo or KDDI.
You can keep your regular SIM in your phone, use Journey Japan eSIM for mobile data, and switch between lines through your phone settings.
Choose the Journey Japan eSIM plan that fits your stay and install it before you travel to Japan.
