The terms you will meet when you set up a travel eSIM on iPhone, explained in one or two sentences each. Missing a term? Tell us.
- eSIM
- A SIM built into the phone as a chip. Instead of inserting a plastic card, you download a carrier profile to it. Every iPhone from the XS and XR onward has one.
- EID
- The eSIM Identifier, a 32-digit number unique to your phone's eSIM chip. You find it in SettingsGeneralAbout; if it is there, your iPhone supports eSIM.
- ICCID
- The number of a specific SIM or eSIM profile. Support teams often ask for it when you report a problem with a plan.
- eSIM profile
- The downloaded package that holds one carrier plan. An iPhone can store several profiles but uses at most two lines at once.
- SM-DP+ address
- The server address from which an eSIM profile is downloaded. You type it, with the activation code, when you add an eSIM manually instead of scanning a QR code.
- Activation code
- The one-time code that ties a profile download to your purchase. It is usually printed next to the QR code.
- eSIM QR code
- A code that contains the SM-DP+ address and activation code. Scan it once; most codes stop working after the profile is installed.
- Dual eSIM
- Two eSIM lines active at the same time. Supported on iPhone 13 and newer, which lets you keep your home line and a travel line together.
- eSIM-only iPhone
- An iPhone with no physical SIM tray, such as US models from iPhone 14 onward and iPhone Air in every market.
- Carrier lock
- A restriction that ties a phone to one carrier. A locked iPhone cannot install a travel eSIM from another provider. "No SIM restrictions" in About means it is unlocked.
- Data Roaming
- A per-line switch that lets the line use networks outside its home country. Turn it on for the travel eSIM and off for your home line.
- Travel eSIM
- A prepaid data plan for use abroad, bought from an international provider and installed as a second line. Most are data-only.
- Data-only plan
- A plan with mobile internet but no phone number or SMS. Calls and messages go through apps such as iMessage, FaceTime or WhatsApp.
- Fair-use policy
- A rule on unlimited plans that lowers speed after a set amount of data. Check the threshold on the plan card before buying.
- Hotspot cap
- A limit on how much data you can share with other devices through Personal Hotspot, common on unlimited travel plans.
- Regional and global plans
- One eSIM that works in a group of countries, such as Europe or Asia, or worldwide. Handy on trips with several borders.
- Top-up
- Adding data or days to an eSIM that is already installed, instead of installing a new profile.
- Low Data Mode
- An iOS setting per line that reduces background data use. Useful on fixed-size travel plans.