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eSIMs come with their own vocabulary — most of it borrowed from carrier and SIM-card jargon that doesn’t quite mean the same thing on a digital plan. Here’s what the terms mean in the context of Roamly.

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eSIM technology

eSIM — An embedded SIM: a digital SIM card built into your phone, instead of a physical plastic card you slot in. You don’t get anything in the post — you download the SIM profile to your device. iSIM — An evolution of eSIM where the SIM is integrated directly into the phone’s main chip rather than a separate eSIM chip. Works the same way from your perspective. SIM profile — The actual data (carrier info, your phone number, account credentials) that makes a SIM a “SIM”. With eSIM, the profile is downloaded over the internet rather than imprinted on a plastic card. EID — A unique 32-digit ID for your phone’s eSIM hardware (like a serial number for the eSIM chip). Some operators need this to set up your eSIM. Find it in Settings → General → About on iPhone, or Settings → About → SIM status on Android. ICCID — A unique ID for an individual SIM profile (not the device). Each eSIM you install has its own ICCID. Mostly used for support. QR code activation — The most common way to install an eSIM: your phone’s camera scans a QR code that contains the SIM profile data. Roamly provides this QR code at install time. Manual install — Alternative to QR code: you type in an “SM-DP+ address” and “activation code” by hand. Slower, but works if you can’t scan a QR code (e.g. installing on a phone that’s the only screen you have). More on manual setup → Dual SIM — A phone that can have two active SIMs at once (one physical + one eSIM, or two eSIMs). Lets you keep your home number active alongside a Roamly travel eSIM.

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Plans

Country plan — Roamly plan that covers a single country (e.g. Japan, Italy). Cheaper per GB than a regional plan if you’re only going to one destination. Regional plan — Plan that covers a group of countries (e.g. Asia-Pacific, Europe, Latin America). Best for multi-country trips — one eSIM works across all included countries with one shared data pool. Validity — How long your plan stays active from first use. A “30-day” plan expires 30 days after you first connect to a network at your destination, regardless of how much data is left. Data allowance — How many GB of mobile data your plan includes. When it runs out, you can top up or buy a new plan. Top-up — Adding more data or extending validity to an existing eSIM. Most Roamly plans support top-ups so you don’t need to install a new eSIM. How to top up →

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Networks

3G / 4G / 5G — Generations of mobile network speed. 5G is fastest, 3G slowest. Roamly plans connect to whatever’s available — most modern destinations have 4G or 5G coverage. APN — Access Point Name: a setting that tells your phone which network gateway to use. Roamly eSIMs auto-configure this; you almost never need to touch it. More on APN settings → Data roaming — Using mobile data on a network that isn’t your home carrier. Roamly eSIMs only work via roaming, so the data roaming toggle on your Roamly line must be on. (This won’t trigger charges from your home carrier — those come from the home plan, not Roamly.) Primary line / Secondary line — On a dual-SIM phone, your home SIM is the primary line and Roamly is the secondary (or vice versa). You can choose which line handles calls, texts, and mobile data independently.

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Travel

Activation — The moment your plan starts counting down. For most Roamly plans this is when your eSIM first connects to a network at your destination, NOT when you install it. So you can install at home days before flying without burning validity. Hotspot / tethering — Sharing your eSIM’s mobile data with other devices (laptop, tablet) by turning your phone into a Wi-Fi hotspot. Roamly plans support this on most networks. More on hotspot → Coverage — Which networks your eSIM can connect to in a given country. Roamly partners with multiple carriers per country and switches between them based on signal strength. Phone number — Roamly is data-only — your travel eSIM doesn’t come with a phone number for calls or SMS. Keep your home SIM active to receive calls/texts, and use Wi-Fi calling or apps like WhatsApp for voice while abroad. More on calls and texts →