Introduction
In this article, you'll learn what an eSIM is, how it works, how it compares to a traditional physical SIM card, and how to purchase and activate an eSIM in just a few minutes at esim.vn.
An eSIM (embedded SIM) is a digital SIM that lets you activate a cellular plan without using a physical SIM card. Instead of inserting a removable card into your device, an eSIM is a programmable chip built directly into your phone or tablet.
An eSIM works exactly like a traditional SIM card - it connects your device to a mobile network and enables cellular connectivity. Most modern smartphones and tablets support eSIM technology today, though some older devices may not have this capability.
How Does an eSIM Work?
Activating an eSIM is simple and only requires an internet connection and a unique digital code, usually provided as a QR code. Once your eSIM has been activated and provisioned, you can use it to connect to a mobile network even without an internet connection. The initial setup requires internet access to download the eSIM profile, but after that, the eSIM functions normally for cellular connectivity, just like a regular SIM.
An eSIM provides the same signal strength as a physical SIM card and doesn't drain your phone's battery any differently. If you experience network issues, they're typically caused by coverage limitations in that particular area, not by the type of SIM you're using.
eSIM vs. Physical SIM
Both eSIMs and physical SIM cards serve the same purpose when it comes to mobile connectivity: connecting your device to a mobile network. The main differences are:
Physical Form: A physical SIM is a removable plastic card; an eSIM is a digital chip built into your device.
Installation: Physical SIMs require opening your device's SIM tray; eSIMs are installed digitally via a QR code, with no physical action needed.
Portability: An eSIM must be removed from one device before it can be installed on another, while physical SIMs can easily be moved between devices.
Dual SIM Support: eSIMs free up the physical SIM tray slot, allowing some devices to support two eSIMs, two physical SIMs, or one of each.
Convenience: eSIMs can be purchased and activated instantly before you travel, while physical SIM cards require a trip to a store or waiting for delivery.
Using Multiple Phone Numbers
You can have two phone numbers on one device if it supports Dual SIM technology. This lets you hold two eSIMs, two physical SIMs, or one of each at the same time. This is useful for separating work and personal numbers, or for using an international travel eSIM without removing your home carrier's SIM - which is one reason more and more travelers are switching to eSIM for business trips and vacations abroad.
That said, each SIM card, whether physical or digital, supports only one unique phone number. You cannot have the same phone number active on both a physical SIM and an eSIM at the same time.
If you want to move your existing phone number from a physical SIM to an eSIM, you'll need to contact your network provider. They will transfer your number to the eSIM and deactivate the old physical SIM card.
How to Buy and Activate an eSIM at esim.vn
Unlike having to visit a store or wait for a physical SIM to be delivered, getting an eSIM through esim.vn is entirely online and takes just a few minutes:
Find your destination: Visit the esim.vn website and search for the country or region where you'll be using your eSIM (for example, Japan, Thailand, or Europe).
Choose the right plan: Compare data plans by data allowance, validity period, and price to pick the option that best fits your trip.
Order and pay: Complete your order and pay securely online, directly on the website.
Get your eSIM instantly: As soon as payment is confirmed, your eSIM code (as a QR code) is sent immediately to your email and also appears in your personal account on esim.vn.
Install your eSIM: Scan the QR code with your phone to install the eSIM, following your device's on-screen instructions (iOS or Android).
With this process, you're fully in control of your timing - you can buy an eSIM at the very last minute before your flight and still have connectivity as soon as you land.
Managing Your eSIM in Your esim.vn Account
One of the biggest advantages of buying an eSIM from esim.vn is being able to fully manage it yourself, without needing to call support or wait for help. In the eSIM Management section of your personal account on the website, you can:
Check your eSIM status (activated, active, or expired).
Track your data usage and remaining balance in real time.
Top up additional data as soon as your plan is running low, without needing to buy a new eSIM or reinstall anything.
Regularly checking your data usage helps you top up before you run out, avoiding connectivity interruptions while abroad - especially useful on longer trips or when you rely heavily on maps and video calls.
As for removing an eSIM: there's nothing unsafe about it. If your data plan has expired, you no longer need it, or you need to free up an eSIM slot for a new plan, you can safely remove it at any time. Keep in mind that if your plan still has remaining data or hasn't expired, you'll need to reinstall the eSIM (by scanning the QR code again) if you want to keep using it on the same device or a different one.
An eSIM can also be tracked in the same way as a physical SIM card - your location can be identified through your carrier's network in the country you're using, regardless of which type of SIM is installed.
Frequently Asked Questions
Does eSIM work on every phone?
No, not all devices support eSIM. Be sure to check the list of eSIM-compatible devices before purchasing, since some older models or carrier-locked phones may not support it.
Do I need to wait for delivery when buying an eSIM from esim.vn?
No. The entire process - from ordering and payment to receiving your activation code - happens online and instantly. You can buy an eSIM from home, at the airport, or anywhere with an internet connection.
What if I run out of data during my trip?
Simply go to the eSIM Management section in your personal account to top up more data instantly, with no need to buy a new eSIM or reinstall from scratch.