Dual SIM FAQ: Top 10 Questions About Using eSIM and Physical SIM Together
Using a physical SIM and an eSIM together has become the standard for modern connectivity, especially for travelers. However, managing two lines can raise a lot of questions. Does it drain battery? Can I use WhatsApp on both numbers? How do I stop my home carrier from charging me? We've compiled the top 10 most frequently asked questions about dual SIM usage in 2026 to clear up the confusion.
1. Can I receive calls on both numbers at the same time?
Yes and no. Both lines are in "Standby" mode, meaning you can receive a call on either line. However, once you answer a call on Line A, Line B effectively becomes busy or disconnected for the duration of that call (unless you have "Wi-Fi Calling" enabled on Line B and it can piggyback on Line A's data—a feature called "Backup Calling" on newer iPhones).
2. Does using two SIMs drain my battery faster?
Technically, yes, but it's negligible on modern devices. Your phone has to maintain a connection to two different towers, which uses slightly more power. However, the battery drain is often caused by a weak signal on one of the lines rather than the dual SIM function itself. If you are in an area with poor reception for your secondary line, temporarily turning it off can save significant battery.
3. Can I use WhatsApp with two different numbers?
Yes! On Android, many phones have a "Dual Messenger" or "Parallel Apps" feature that lets you clone WhatsApp. On iPhone, you can use the standard WhatsApp Messenger app for your personal number and the WhatsApp Business app for your secondary/travel number. Both can run simultaneously.
4. How do I ensure I don't pay roaming charges on my home SIM?
This is the #1 fear for travelers. The solution is simple: Go to your phone settings, select your Home/Physical SIM, and ensure Data Roaming is toggled OFF. Do not turn off the line itself if you want to receive SMS (like bank OTPs). Just kill the data connection for that specific line.
5. What is "Allow Cellular Data Switching"? Should I use it?
On iPhone, this feature allows your phone to use data from the other line if your primary data line has a weak signal. Travelers should turn this OFF. If your travel eSIM signal drops for a second, your phone might switch to your home SIM for data, triggering a $10/day roaming pass instantly.
6. Can I store more than one eSIM?
Absolutely. You can store 8+ eSIM profiles on most modern devices (iPhone 14+, Pixel 7+). Think of it like a wallet of digital cards. However, typically only two lines (one physical + one eSIM, or two eSIMs) can be active (turned "On") at any given moment.
7. Will iMessage work with my Travel eSIM?
Yes. You can keep your primary number set for iMessage send/receive. Your phone will simply use the data connection from your Travel eSIM to send the messages. You do not need to register your temporary travel number with iMessage.
8. Is 5G available on both lines?
Yes, on iPhone 13 and newer (and comparable Android flagships), 5G is supported on both active lines simultaneously. However, using 5G on two lines may increase battery consumption.
9. Can I use a Personal Hotspot with my Travel eSIM?
Generally, yes. Most RoamHoliday plans support hotspot/tethering. You just need to ensure your device is using the Travel eSIM for cellular data when you enable the hotspot.
10. What happens if I accidentally delete my eSIM?
eSIMs are usually one-time install. If you delete it, you cannot simply scan the code again. You would need to contact customer support to issue a new eSIM. Therefore, never delete your eSIM to troubleshoot connectivity issues; always just toggle it off instead.
Still Have Questions?
Our support team is available 24/7 to help you manage your dual SIM setup. Ready to travel? Get a hassle-free eSIM from RoamHoliday and stay connected on your terms.
Find Your Plan