What Is an eSIM and How Does It Work?

🤔 What Is an eSIM?

An eSIM, short for embedded SIM, is a digital SIM built directly into your device that replaces a physical plastic SIM card. Instead of inserting a card, you activate a mobile plan by downloading your carrier profile, including your phone number and plan details, using a QR code or mobile app. This allows you to switch carriers, manage multiple plans and connect securely without swapping SIMs.

Once installed, an eSIM works exactly like a physical SIM. It connects your device to the StarHub network so you can make calls, send messages and use mobile data.

With an eSIM, you can

• Activate a mobile plan in minutes

• Store multiple numbers on one phone

• Switch between work, personal and travel lines

• Add overseas data plans digitally

• Avoid handling or losing physical SIM cards

   

⚙️ How does an eSIM Work?

An eSIM works just like a physical SIM once it is active. It connects your phone to the StarHub mobile network so you can make calls, send messages and use mobile data.

The main difference is how the SIM is set up.

Instead of inserting a plastic SIM card, your phone downloads the SIM information digitally onto a built-in chip called the eUICC. This chip securely stores your phone number, mobile plan and network settings.

When you sign up for a StarHub eSIM, StarHub creates a digital SIM profile for your number. Your phone then downloads this profile over the internet and saves it on the eSIM chip. Once this is done, your phone connects to the StarHub network automatically, just as it would with a physical SIM.

How eSIM Activation Works

1. You sign up for a StarHub eSIM plan

2. You receive a QR code or activation link

3. You scan it in your phone’s eSIM settings

4. Your phone downloads and activates the eSIM

That’s it. Your number and mobile plan are now live on your device.

🚀 Why More People Are Switching to eSIM

eSIM removes the need for physical SIM cards.

It allows you to:

• Activate a new line in minutes

• Switch phones without waiting for a replacement SIM

• Use more than one mobile plan on the same device

Because the SIM is embedded in the device, it is also harder to remove or misuse if the phone is lost, which improves security.

🆚 eSIM vs. Physical SIM

🌟 Why eSIM makes Life Easier

Beyond replacing a physical SIM card, eSIM fundamentally changes how you use and manage mobile connectivity. It makes travel, security, and everyday mobile use simpler and more flexible.

#1 Global Roaming made Simple 🌍

With eSIM, you no longer need to hunt for a local SIM card when you travel.

You can activate:

• International roaming on your StarHub line

• Or a local travel eSIM for data

All of this is done digitally, before or during your trip.

This means you can:

• Avoid high roaming charges

• Stay connected the moment you land

• Keep your main number active for calls and SMS

For frequent travellers, this removes the stress of finding SIM cards overseas.

#2 Effortless Profile Management ✈️

eSIM lets you store multiple mobile profiles on a single device.

This makes it easy to:

• Keep work and personal numbers separate

• Switch between local and overseas plans

• Turn lines on and off instantly

You manage everything from your phone’s settings, with no SIM tray and no ejector tool.

#3 Greater Data Security 🔒

Because eSIMs are built into the phone, they cannot be removed physically.

If your phone is lost or stolen:

• Your SIM cannot be taken out

• Your number cannot be hijacked

• Your line can be suspended remotely

This gives eSIM a major security advantage over traditional SIM cards.

#4 Slimmer and more Powerful Devices 🛠️

Removing the SIM tray creates more space inside smartphones.

Manufacturers use that extra space for:

• Larger batteries

• Better cameras

• Improved water resistance

This allows phones to become thinner, lighter, and more powerful without sacrificing performance.

#5 Improved Network Reliability 📶

eSIMs allow mobile carriers to:

• Push updates remotely

• Optimise network settings

• Fix SIM-related issues without replacements

This reduces downtime and ensures your device always runs with the latest network configuration.

💡 4 Simple Tips for New eSIM Users

If this is your first time using an eSIM or managing multiple mobile profiles, these tips will help you avoid common problems and get the most out of your StarHub eSIM.

1. Label Your eSIM Profiles 📁

If you use more than one eSIM profile, give each one a clear name.

For example:

• Personal

• Work

• Travel

• Overseas Data

This makes it much easier to switch between lines and avoids using the wrong number or data plan by mistake.

2. Activate Your eSIM Over WiFi 📶

Always activate a new eSIM while connected to WiFi.

Your phone needs a stable internet connection to download the SIM profile. Using WiFi prevents:

• Interrupted downloads

• Activation failures

• Incomplete network setup

   

3. Research Carriers Before You Travel ✈️

Not all mobile carriers support eSIM.

Before travelling, check:

• Which carriers in your destination country support eSIM

• Whether StarHub roaming covers that country

• Whether a local travel eSIM is cheaper

This ensures you stay connected as soon as you arrive.

4. Keep Your Primary Number on eSIM 📱

For better security, keep your main number on eSIM instead of a physical SIM.

If your phone is lost or stolen:

• A physical SIM can be removed

• An eSIM cannot

This protects your number and reduces the risk of identity theft or account hijacking.

❓ Frequently Asked Questions (FAQ)

#1 How to Check If Your Phone Supports eSIM

You can quickly check whether your phone supports eSIM using one of these methods.

#2 How to Activate and Install an eSIM

After signing up for a StarHub eSIM plan, you will receive a QR code by email or in the StarHub App.

To activate it:

1. Connect your phone to WiFi

2. Open Settings

3. Tap Add eSIM

4. Scan the QR code

5. Follow the on-screen instructions

Your phone will download your mobile number and network settings and connect automatically.

👉 Tip: You do not need to remove your physical SIM to use eSIM. Both can stay active.

#3 How Long Does eSIM Activation Take?

Most StarHub eSIMs activate within a few minutes after scanning the QR code.

If you are transferring your number from another carrier, it can take longer depending on the port-in process, but you will be notified once it is complete.

#4 How to Transfer Your eSIM to a New Phone

When you change phones, your eSIM does not move automatically. You need to activate it on your new device, either by transferring it directly or by scanning a new QR code from StarHub.

The exact method depends on your phone.
 

👉 iPhone to iPhone (Quick Transfer)

If both iPhones support eSIM Quick Transfer, this is the easiest way.

1. Keep both phones near each other with WiFi and Bluetooth turned on

2. On your new iPhone, go to Settings → Cellular → Add eSIM

3. Choose Transfer from Nearby iPhone

4. Follow the on-screen instructions on both phones

Your number and plan move to the new iPhone automatically.
 

👉 Android to Android or Android to iPhone (QR Code)

1. On your old phone, go to Settings → SIM Manager and remove the eSIM

2. Open the StarHub App or email to retrieve your QR code

3. On your new phone, go to Settings → Add eSIM

4. Scan the QR code and complete setup

Your StarHub number and plan are now active on the new device.

#5 How to Remove an eSIM

Removing an eSIM deletes the mobile profile from your device. It does not cancel your StarHub mobile plan unless you request cancellation separately.

You can remove an eSIM at any time from your phone’s settings.

👉 On iPhone

1. Open Settings

2. Tap Cellular or Mobile Service

3. Select the eSIM plan you want to remove

4. Tap Delete eSIM or Remove Cellular Plan

5. Confirm when prompted

👉 On Android

1. Open Settings

2. Tap Connections or Network and Internet

3. Tap SIM Manager or Mobile Networks

4. Select the eSIM

5. Tap Remove or Delete eSIM and confirm

🛒 Where to Buy eSIM in Singapore?

You can easily buy and activate your StarHub eSIM online without visiting a store or inserting a physical SIM card.

Our eSIM works just like a regular StarHub mobile line, supporting calls, SMS, 5G data and roaming on eligible plans, while giving you the convenience of faster activation, easier phone upgrades and better security.

If you’re ready to hop aboard, feel free to pick up an eSIM with our 5G Unlimited+ mobile plans!