eSIM glossary: the terms you'll meet, explained
Every term you will meet in your phone's settings, in our emails and on the product page, in one or two sentences each. Alphabetical.
The four terms that matter most: an eSIM is a SIM downloaded into the phone; the EID is your phone's eSIM serial number (dial *#06# to see it); the QR code carries the activation details for one eSIM profile; and data roaming is the switch that lets the eSIM use a network abroad, which must be on for the travel line and off for your home line.
- Activation
- The moment a plan starts counting days. For ETravelSim data plans this is the first time the eSIM connects to a network in the destination, not when you install it, so you can install weeks ahead. See how to activate an eSIM.
- Activation code (manual code)
- The text version of the QR code, in the form LPA:1$server$code. You type or paste it when a camera is not available, for example when installing on the same phone that is showing the code. It is in your confirmation email next to the QR.
- APN (Access Point Name)
- The gateway name your phone uses to reach the internet through a network. Most eSIMs set it automatically. If you have signal but no data, the APN is the first thing to check. Values and steps are in the APN guide.
- Carrier lock (network lock)
- A restriction set by the carrier that sold you the phone so it only works with their SIMs, including eSIMs. A locked phone cannot use a travel eSIM until the carrier unlocks it, which is usually free once the contract is paid off. How to check.
- Coverage
- Where a network has signal. A travel eSIM's coverage is the coverage of the local network it connects to. In the USA that is a major national 5G network; in Europe it switches between the strongest partner in each country.
- Data only plan
- A plan with internet access but no phone number, minutes or SMS. Calls go over WhatsApp or FaceTime. Most travel eSIM plans are data only, and your home SIM keeps handling calls to your own number.
- Data + calls plan
- A plan that includes a local phone number and minutes alongside the data. ETravelSim offers these on selected destinations, for example with 100 minutes. Like data plans, validity starts the first time the eSIM connects in the destination.
- Data roaming
- A switch in your phone, one per line, that allows that line to use a network other than its home network. A travel eSIM is technically always roaming, so this must be on for the eSIM line. Turn it off for your home SIM to avoid charges from your carrier.
- Dual SIM
- A phone that can run two lines at once, typically one physical SIM and one eSIM. You choose which line handles calls, which handles data, and which is default for messages. Every eSIM capable phone is dual SIM. Setup guide.
- EID (eUICC Identifier)
- A 32 digit serial number for your phone's built in eSIM chip. Dial *#06# or look in Settings, About, to see it. Its presence tells you the phone supports eSIM. Support may ask for it when reissuing a profile. How to find it.
- eSIM (embedded SIM)
- A SIM built into the phone as a chip, with the carrier profile downloaded onto it instead of supplied on a plastic card. Became mainstream with the 2018 iPhone XS/XR and Google Pixel 3. Can hold several profiles; most phones let one or two be active at a time. Longer explanation.
- eSIM profile
- One downloaded SIM. Each plan you buy from a provider is one profile; recharging an existing ETravelSim eSIM adds data to the same profile rather than creating a new one, on destinations that support top-ups.
- eUICC
- The technical name of the eSIM chip (embedded Universal Integrated Circuit Card). You will only meet it in the EID's full name.
- Fair use policy (FUP)
- The rules behind an unlimited plan. On most ETravelSim unlimited plans you get 4 GB a day at full speed, then 1 Mbps until the 24-hour reset. Japan and Thailand unlimited plans have no daily cap, China and Hong Kong slow to 128 kbps after 3 GB, and Truly Unlimited plans have no cap. Hotspot on unlimited plans depends on the destination. Full policy.
- 5G / 4G LTE / 3G
- Generations of mobile network. 5G is the fastest and now standard in cities across the USA, Europe, the Gulf and East Asia. 4G LTE is the fallback indoors and in rural areas and is fine for video. 3G is being switched off in most countries.
- Hotspot (tethering)
- Sharing your phone's data with another device over Wi-Fi, Bluetooth or cable. Allowed on every ETravelSim GB plan. On unlimited plans it depends on the destination: allowed in Thailand, Indonesia and Ireland and on all Truly Unlimited plans, not on most other unlimited plans. How to use it.
- ICCID
- The serial number of a SIM profile (19 or 20 digits), as opposed to the EID, which identifies the chip. Each eSIM you install has its own ICCID. It appears in Settings under the line's details and on your order confirmation.
- Installation
- Downloading the profile onto the phone by scanning the QR code or entering the manual code. Needs an internet connection, usually Wi-Fi. Installing does not start the plan.
- LPA (Local Profile Assistant)
- The software inside your phone that downloads and manages eSIM profiles. The letters appear at the start of every manual activation code.
- Local network / partner network
- The carrier in the destination whose towers your eSIM connects to. ETravelSim does not own towers; it buys access from major local networks, which is why a travel eSIM gets local speeds.
- Mbps
- Megabits per second, the unit of connection speed. 1 Mbps handles maps, messaging and email. Video calls want 2 to 4 Mbps. HD streaming wants 5 Mbps or more. Do not confuse with MB (megabytes), which measures data used.
- MB / GB
- Megabytes and gigabytes, units of data. 1 GB is 1,024 MB. A typical travel day uses 500 MB to 1 GB. The calculator estimates yours.
- Network selection
- A phone setting, Automatic by default, that picks which local network the line uses. Leave it on Automatic unless support asks you to choose a network by hand.
- Primary / secondary line
- Labels your phone gives to the two active lines. Travellers usually keep the home SIM as primary for calls and messages and set the eSIM as the line for mobile data.
- QR code
- The square barcode containing your eSIM's download address and activation code. One QR installs one profile, once. If you delete the eSIM, you need a new QR from support. Lost it?
- Recharge (top up)
- Adding data or days to an eSIM you already have installed, without a new QR code. Available on most eSIMs (Japan and Vietnam need a new eSIM instead); bought from the app or the recharge page; applies within minutes. How to.
- Regional plan
- A plan that works in several countries, such as the Europe eSIM (34 countries) or the Asia eSIM (14 countries). The phone switches networks at the border without any action from you.
- Roaming
- Using a network other than the one that issued your SIM. For your home carrier this is what triggers day pass charges. For a travel eSIM it is the normal state and costs nothing extra.
- SM-DP+ (server address)
- The server your phone downloads the eSIM profile from. The address is embedded in the QR code; on some phones you enter it separately when installing by hand.
- Throttling
- Reducing speed after a usage threshold. On most unlimited plans this means 1 Mbps after 4 GB in a day, with full speed returning at the reset; some destinations have no daily cap. Fixed data plans are not throttled; they stop when the data is used.
- Transfer
- Moving an eSIM to a new phone. iPhones can transfer eSIMs directly between devices; otherwise support issues a new QR. Guide.
- Unlimited plan
- A plan with no total data cap for its validity period, subject to the fair use policy above. Hotspot depends on the destination. Usually the cheapest option for heavy users on trips up to two weeks.
- Validity
- How many days a plan lasts once it starts: from 1 to 30 days, depending on the product. Days run continuously, including days you do not use data.
- VoLTE / Wi-Fi calling
- Technologies for carrying voice calls over 4G or over Wi-Fi. Relevant if you keep your home SIM active for calls abroad: with Wi-Fi calling enabled, calls to your home number can connect over the eSIM's data or hotel Wi-Fi, often at no roaming charge.
Still unsure about a term?
Ask support on WhatsApp, 24/7. If a word on this page tripped you up, tell us and we will rewrite the entry.