Keep your number and WhatsApp abroad

onesim is data only, with no phone number of its own. Your phone runs both lines at once: your usual SIM keeps your number for calls and texts, and onesim carries your data.

WhatsApp is tied to your phone number, not to the line that carries your data, so there is nothing to change: same number, same chats. If it asks you to verify your number again, the code comes by text or call, so keep your usual SIM switched on.

With your usual SIM on, calls and texts can still reach your number, sign-in codes from your bank included. What they cost abroad is up to your provider: with a SIM from the EU, they’re billed as at home in the EU; elsewhere, check before you go. To call home, use WhatsApp or FaceTime over your data.

Before you fly, check that Data Roaming is off on your usual SIM, so it doesn’t use data abroad. When you land, your iPhone may offer to turn on your travel eSIM: choose Travel eSIM and Current eSIM (Current SIM on some iPhones). Travel eSIM Only would switch your number off.