Do I keep my number and WhatsApp?
Yes and yes. Your eSIM only handles data — everything tied to your number stays put.
Yes — your number stays yours. A FullBars eSIM is a data plan. It doesn't replace your SIM or your number; it sits alongside them.
WhatsApp is tied to your number, not your SIM, and it talks over whatever data connection your phone has. With your FullBars eSIM handling data, WhatsApp carries on exactly as normal — same chats, same number, nothing to re-verify.
Calls and texts
Keep your normal SIM enabled and you can still receive calls and texts on your number (handy for banking codes). One thing to know: answering a call or sending an SMS goes over your home network, so your home provider's roaming rates apply to those. Most people let calls go to WhatsApp and leave it at that.
If you want zero risk of accidental roaming charges, you can turn your home SIM off entirely — you just won't get calls/texts on your number while it's off.