Travel eSIMs are designed for mobile data, not for traditional calls or SMS. When you travel overseas with a travel eSIM, you usually get a data-only plan. This means you cannot make or receive standard phone calls or send SMS using that eSIM's number, because the eSIM does not come with a voice or messaging service. Instead, you rely on internet-based apps and the capabilities of your phone to stay connected.
Understanding Data-Only Plans
A travel eSIM from TPG Mobile is a data-only product. It provides mobile data for internet access while you are abroad, but it does not include a local phone number for calls or texts. The eSIM itself does not give you a separate mobile number for voice or SMS. You use the data connection to access the internet, which then allows you to use apps that handle calls and messages over the internet.
What You Can Do with Data
- Use messaging apps like WhatsApp, Telegram, or Signal to send texts and make voice or video calls.
- Make FaceTime audio and video calls on Apple devices (iPhone, iPad, Mac) if both parties use Apple services.
- Use iMessage to send texts, photos, and videos between Apple devices.
- Access email, social media, and other online services that use data.
These apps work over the internet, so they do not require a traditional mobile network voice service. You just need a stable data connection.
The Primary SIM and Your Usual Number
Your mobile phone typically has two SIM slots: a physical SIM and an eSIM, or two eSIMs. When you travel with a travel eSIM, you can keep your usual Singapore SIM in the phone. This is important because your primary SIM-the one with your usual mobile number-may still be able to make and receive calls and SMS, depending on your home operator's roaming services. However, using your home SIM for calls and texts overseas often incurs roaming charges. Travel eSIMs do not replace your home SIM; they add a data connection alongside it.
How to Use Your Primary SIM While Travelling
You can set your phone to use the travel eSIM for mobile data, while keeping your primary SIM active for calls and SMS. This way, you can still receive calls and texts on your usual number, but you may be charged international roaming rates by your home operator. Some phones let you choose which SIM to use for voice calls and which for data. You can also disable the primary SIM entirely and rely only on the travel eSIM for data, then use internet-based apps for communication.
Wi-Fi Calling and Its Uncertainties
Wi-Fi calling is a feature that lets you make and receive calls over a Wi-Fi connection instead of a cellular network. Some mobile operators support Wi-Fi calling for their customers. With a travel eSIM, Wi-Fi calling is not guaranteed. The feature depends on your phone model, your home operator's support, and the travel eSIM provider's compatibility. If your home operator supports Wi-Fi calling and your phone is set up for it, you might be able to use your usual number over Wi-Fi while abroad. But this is not a standard feature of travel eSIMs, and it may not work with a data-only eSIM. Always check with your home operator and the eSIM provider about Wi-Fi calling compatibility before relying on it.
Using Apps for Calls and Messages
The most reliable way to make calls and send messages with a travel eSIM is to use internet-based apps. Apps like WhatsApp, FaceTime, and iMessage are popular in Singapore and work well over data. They use your internet connection, so you do not need a traditional voice or SMS plan.
WhatsApp uses your phone's internet connection to send messages, make voice calls, and make video calls. It works on both Android and iPhone. You need to have WhatsApp installed and registered with your usual mobile number before you travel. Once abroad, as long as you have data from your travel eSIM, you can use WhatsApp normally. Note that WhatsApp uses your phone number for verification, but it does not require an active cellular voice plan to function.
FaceTime and iMessage
FaceTime and iMessage are built into Apple devices. FaceTime allows audio and video calls between Apple devices over the internet. iMessage sends texts, photos, videos, and other media between Apple devices, also over the internet. These services use your Apple ID and an internet connection, not a cellular voice plan. If you have an iPhone, you can use FaceTime and iMessage with your travel eSIM data. You can also enable iMessage and FaceTime with your Apple ID, so you can send and receive messages on your iPad or Mac, even if your iPhone is not connected to cellular.
What About Traditional Calls and SMS?
If you need to make a traditional call to a landline or a mobile number that is not on an internet app, a travel eSIM alone may not help. You could use an internet-based calling service like Skype or Google Voice, but those require an account and may have fees. Alternatively, you can use your home SIM with roaming, but that can be expensive. For most travellers, using internet apps for calls and messages is the most cost-effective and convenient approach.
Receiving SMS Verification Codes
Some online services send SMS verification codes for security. If you need to receive a one-time password (OTP) while abroad, a data-only travel eSIM does not provide SMS. You would need to have your primary SIM active and able to receive SMS, which may incur roaming charges. Some banks and services also offer verification through apps or email, so check what options are available to you.
Planning Your Communication Setup
Before you travel, think about how you want to stay in touch. If you plan to use WhatsApp, FaceTime, or iMessage, make sure they are set up and linked to your accounts. Consider downloading offline maps and important documents. Decide whether you want to keep your primary SIM active for calls and texts, knowing that roaming charges may apply. Set up your phone to use the travel eSIM for data, and test your apps before you leave. This way, you can connect on arrival without surprises.
Keep Your Usual SIM in the Phone
Keeping your usual SIM in the phone is often a good idea. It allows you to receive SMS verification codes for banking and other services, and it lets you stay reachable on your usual number if needed. You can manage your phone settings to use the travel eSIM for data while keeping the primary SIM active for calls and SMS. This approach gives you flexibility, but remember that using your primary SIM for calls and texts overseas may incur roaming charges from your home operator.
Making the Right Choice for Your Trip
Before you travel, consider how you normally communicate. If you rely on WhatsApp, FaceTime, or iMessage, a travel eSIM with sufficient data will cover most of your needs. If you must make traditional phone calls to local numbers abroad, you may need a different solution, such as a local SIM card with voice service or an internet calling app that offers low-cost international calls. For many travellers, a data-only eSIM plus internet apps is enough to stay in touch with family, friends, and colleagues.
Planning Ahead
Before you depart, check which apps you use most and ensure they are installed and set up. Verify that your primary SIM is working and decide whether you want to keep it active for roaming. Test your travel eSIM's data connection before you leave, if possible, by installing it and connecting to Wi-Fi at home. On arrival, enable the travel eSIM for data and switch off data roaming on your primary SIM to avoid unexpected charges. Remember that a travel eSIM is a data-only service, so plan your communication needs around internet-based tools.
