eSIM
Definition
A digital SIM built into your phone that lets you add a mobile line by scanning a QR code or using a carrier app.
eSIM, explained
An eSIM (embedded SIM) is a SIM chip soldered into the phone that can hold one or more carrier profiles downloaded over the internet. You add a line by scanning a QR code or through a carrier app, with no plastic card. Many recent phones support eSIM, and dual-SIM phones can run two numbers at once, making eSIM an easy way to add a second long-term line. Be careful with travel eSIMs: many are data-only and include no phone number, so they cannot receive SMS codes. Carrier-locked phones may also refuse another carrier's profile.
Related terms
SIM card
The small chip that identifies your line to a mobile carrier and links your phone to your number.
Carrier
A mobile network operator or provider that issues phone numbers and delivers calls and texts.
MVNO
A mobile virtual network operator: a phone company that sells service using another carrier's network.
Where you'll meet this term
How to Receive SMS Online: Get Verification Codes Without Your Own Number
How to receive SMS verification codes online: free public inboxes vs private rented numbers vs VoIP apps vs a second SIM, with risks and setup steps.
Read the guide →Getting startedNon-VoIP vs VoIP Numbers: What's the Difference and Why It Matters for Verification
What non-VoIP numbers are, how apps detect VoIP with line-type lookups, why Google Voice and TextNow get rejected, and when each number type works.
Read the guide →App guidesHow to Use WhatsApp Without Your Own Phone Number
Can you use WhatsApp without number verification or a SIM? Why WhatsApp always checks a number, how to use a virtual one, the 2-step PIN and recycling.
Read the guide →App guidesTwo WhatsApp Accounts on One Phone: Methods and How to Get a Second Number
Run two WhatsApp accounts on one phone with built-in multi-account, WhatsApp Business or dual apps, and learn where to get the second number you need.
Read the guide →Temporary virtual number vs Second eSIM lineTemporary virtual number vs a second eSIM line
A second eSIM gives you a real long-term number on a compatible phone. A temporary virtual number covers one code. Compare setup, cost and recovery.
See the comparison →Temporary number vs Long-term numberTemporary number vs a long-term number you own
A temporary number covers one verification and is then recycled. A long-term number stays yours for recovery. Noir SMS offers temporary numbers only.
See the comparison →