New to eSIMs? You’re in the right place. This glossary explains, in plain English, the terms you’ll encounter when you buy, install, and use a Maya travel eSIM. We’ve organized everything from A to Z, so you can skim for a word or read straight through.
A
Activation: The moment your eSIM “switches on” and connects to a local network. With Maya, activation is automatic; your plan starts counting down once your eSIM connects to a network in your destination, not the second you buy it. So you can set everything up at home and only start using data when you land.
Activation Code: The unique code hidden inside your QR code that tells your phone which eSIM profile to download. If you can’t scan the QR code (say, you’re installing on the same phone that’s showing it), you can usually type this code in manually instead.
Airplane Mode: The phone setting that turns off all wireless signals. Handy to know because a quick toggle of Airplane Mode on and off is the classic first fix if your eSIM isn’t connecting when you arrive somewhere new, it forces your phone to search for a local network again.
Android: Google’s mobile operating system, used by phones like Samsung Galaxy, Google Pixel, and many others. Most recent Android flagships support eSIM, but a few regional models don’t; always check compatibility before you buy (see Compatibility).
APN (Access Point Name): The setting that tells your phone how to reach the mobile internet. Think of it as the “address” your phone dials to connect to the internet through a carrier. With Maya, this is set up for you automatically, so you almost never have to touch it, but if data won’t flow, checking the APN is one troubleshooting step that support may walk you through.
B
Backup eSIM: Keeping a second eSIM profile on your phone as a spare. Because eSIMs are just software, you can store several profiles and switch between them useful if you want a fallback network or a separate plan for a different country.
Bands (Network Bands): The specific radio frequencies a phone and a network use to talk to each other. Different countries and carriers use different bands; modern phones support a wide range, which is why a compatible phone generally works across Maya’s 165+ countries without you having to think about it.
Bundle: Another word for a data plan or package, the amount of data (or unlimited data), and the number of days you’ve purchased. You’ll see “bundle” used interchangeably with “plan” across the eSIM industry.
C
Carrier: A company that operates a mobile network operator (also called an operator or MNO). When you travel with Maya, your eSIM connects to established local carriers in each country on your behalf.
Carrier Lock (Locked Phone): A restriction on some phones that ties them to a single carrier, usually because the phone was purchased on a payment plan. A locked phone may not be able to add a travel eSIM. If in doubt, ask your original carrier to confirm your phone is unlocked (see Unlocked Phone).
Compatibility (Device Compatibility): Whether your specific phone can use an eSIM at all. Two things need to be true: your phone must have eSIM hardware, and it must be carrier-unlocked. Most iPhones from the XS onward and most recent flagship Android phones qualify, but it’s always worth checking your exact model before buying. This is the single most common reason a travel eSIM won’t work.
Coverage: The geographic areas where your eSIM can get a signal. Coverage depends on which local networks the eSIM partners with. Maya covers 165+ countries, including 5G in 125+ of them.
Coverage Map: A map showing where a plan works and what speeds (5G, 4G/LTE) you can expect. Checking the coverage map for your destination before you travel helps set expectations, especially for remote areas.
Cruise Coverage (Cellular at Sea): Special connectivity for when you’re on a cruise ship away from land-based networks, delivered through satellite-linked maritime networks. It’s typically slower and pricier than regular coverage. Maya supports 20+ major cruise lines, so you can stay connected at sea if your plan includes it.
D
Data Plan – What you actually buy: an allowance of mobile internet for a set number of days. Maya’s plans come with unlimited data and range from 3 to 30 days.
Data Roaming – Using mobile data on a network other than your home carrier’s, traditionally, the thing that led to shock bills abroad. A travel eSIM replaces expensive roaming with an affordable local plan. Note: on your phone, you often need to turn the “Data Roaming” toggle ON for your Maya eSIM line, because to your phone the travel eSIM counts as a “roaming” line. This won’t cost you extra; your usage is covered by the plan you bought.
Data-only eSIM: An eSIM that provides internet but not a traditional phone number for regular calls and texts. Most travel eSIMs, including Maya, are data-only, but you can still call and message over the internet using apps like WhatsApp, FaceTime, or Zoom (see VoIP).
Deactivation: When an eSIM profile is switched off or expires. Once a plan’s validity period ends, that profile stops working, though you can usually keep it installed, top it up, or start a new plan later.
Dual SIM: A phone’s ability to run two lines at once, for example, your normal home SIM for calls and texts, plus a Maya eSIM for data. This lets you keep your regular number reachable while using cheap local data abroad.
E
eSIM (Embedded SIM): A SIM card built directly into your phone as software, instead of a small plastic chip you slot in. Because it’s digital, you can buy a plan online and install it in about two minutes by scanning a QR code, no shipping, no shops, no fiddling with a tray. It’s the whole reason travel connectivity got easy. One phone can hold many eSIM profiles and switch between them. What is an eSIM?
eKYC (electronic Know Your Customer): A digital identity check that a handful of countries legally require before a SIM or eSIM can be activated (for example, submitting a passport photo). Most destinations don’t require this, but where it applies, you may be asked to verify your identity in the app before your plan takes effect.
EID: The unique serial number of the eSIM chip built into your phone. It identifies your device’s eSIM hardware during setup. You can usually find it in your phone’s settings, and support may ask for it if you hit an installation snag.
eUICC: The technical name for the reprogrammable chip inside your phone that makes eSIM possible. It’s what lets a single piece of hardware download, store, and swap between different carrier profiles over the air.
F
Fair Use Policy (FUP): The fine print on “unlimited” plans. To keep the network fair for everyone, unlimited plans may run at full speed up to a daily data limit, then slow down (see Throttling) if you exceed typical use. For normal travel maps, browsing, social media, and streaming, most people never notice it.
5G: The latest and fastest generation of mobile network, offering quicker downloads and smoother streaming than 4G, where it’s available. Maya offers 5G in 125+ countries, where 5G isn’t available, your eSIM automatically falls back to 4G/LTE.
4G / LTE: The generation of mobile networks before 5G is still the workhorse of fast mobile internet worldwide. It’s more than fast enough for maps, video calls, and streaming, and it’s available almost everywhere you’ll travel.
G
GB (Gigabyte): The standard unit for measuring mobile data. As a rough guide, 1 GB covers a few hours of browsing and social media or about an hour of standard-definition video. Plans with unlimited data, like Maya’s, mean you don’t have to count gigabytes.
Great Firewall: The nickname for China’s internet restrictions, which block many Western sites and apps (Google, WhatsApp, Instagram, and more). A key travel perk of some eSIMs is that their data is routed through networks outside mainland China, letting you use your usual apps there without a separate VPN, worth checking before a trip to China.
GSMA: The global industry body that represents mobile operators and sets the standards that make eSIMs work the same way across the world. You don’t need to interact with it; it’s just the reason your eSIM behaves consistently across countries.
H
Hotspot (Tethering): Sharing your phone’s internet connection with other devices, such as a laptop, a tablet, or a travel companion’s phone by turning your phone into a portable Wi-Fi point. It’s one of the most useful travel tricks: connect the whole family on one plan. Maya’s plans support hotspot use, so you can get your laptop online from a café with no Wi-Fi.
I
ICCID: The unique ID number of a specific SIM or eSIM profile, which is either an 18 or 22-digit serial number. It identifies your particular plan on the network, and support may reference it when helping you.
IMEI: The unique serial number of your phone itself (not the SIM). You can see it by dialing *#06# on most phones. It’s sometimes used to confirm your device is unlocked and eSIM-capable.
IMSI: A hidden identifier that tells a network which subscriber and home carrier an eSIM belongs to. It works behind the scenes so networks know how to route your connection; you’ll never need to handle it directly.
Installation: The one-time setup where your eSIM profile is downloaded onto your phone, usually by scanning a QR code or tapping a button in an app. With Maya, it takes about two minutes, and you only do it once after that; the eSIM lives on your phone for future trips.
iOS: Apple’s operating system for iPhones. iPhones from the iPhone XS/XR (2018) onward support eSIM; iPhones sold in the U.S. from the iPhone 14 onward are eSIM-only, with no physical SIM tray.
J
Jitter: A measure of how steady your connection is, rather than how fast. High jitter means the timing of your data is uneven, which can make video calls stutter even when speeds look fine. It’s a useful word to know if a call feels choppy despite a strong signal.
K
Kbps / Mbps (data speed): Units for how fast data moves. Kbps (kilobits per second) is slow; Mbps (megabits per second) is the standard unit for modern mobile internet. Higher values are faster. If a plan is throttled after heavy use, speeds may drop from Mbps down toward the Kbps range.
Kill Switch: A VPN feature that instantly cuts your internet if the VPN connection drops, so your real location or data isn’t accidentally exposed. Relevant if you use a VPN alongside your eSIM for privacy or to reach home services while abroad.
L
Latency: The delay between your phone asking for something online and getting a response, measured in milliseconds. Low latency feels instant; high latency makes video calls and games feel laggy. It’s different from speed; you can have fast data with high latency, especially over satellite or cruise connections.
LPA (Local Profile Assistant): The small piece of software on your phone that handles downloading and managing eSIM profiles. It’s what springs into action when you scan an eSIM QR code, working quietly in the background so you don’t have to.
LTE: See 4G / LTE. “LTE” is the technical name you’ll often see in your phone’s status bar for 4G-class speeds.
M
MB (Megabyte): A smaller unit of data; 1,000 MB is roughly 1 GB. Light tasks like sending messages or loading a webpage use only a few MB of memory.
MNO (Mobile Network Operator): A company that owns and runs an actual mobile network and its towers, the big-name carriers in each country. Your travel eSIM connects to these local operators wherever you go.
MVNO (Mobile Virtual Network Operator): A mobile provider that sells service using another company’s network rather than building its own towers. Many travel eSIM brands operate this way, which is how they offer coverage across so many countries.
N
Nano SIM: The smallest size of a traditional plastic SIM card, and the last physical SIM format before eSIM. Knowing the term helps when comparing old-style travel SIMs (which you have to order and swap) with an eSIM (which you just download).
Network: The system of towers and infrastructure that carries your calls and data. When people say your eSIM is “searching for a network,” it’s looking for a local carrier’s signal to lock onto.
O
Operator: Another word for a carrier or mobile network provider (see MNO).
OTA (Over-the-Air): Anything delivered to your phone wirelessly rather than through a cable or physical card, including your eSIM profile itself. “Over-the-air provisioning” is the magic that lets you install a SIM by scanning a code instead of waiting for one in the mail.
P
Physical SIM: The traditional plastic SIM card you slot into a tray. The opposite of an eSIM. Your phone can often use both at once, letting you keep your physical home SIM active while adding a Maya eSIM for data.
PIN: A short security code that can be set to lock a SIM. Travel eSIMs usually don’t require a SIM PIN, but it’s good to know the term if your phone ever asks for one.
Profile: The digital “SIM card” that gets downloaded onto your phone when you install an eSIM. Each plan is a separate profile, and your phone can hold several, so you might have a Maya profile for travel and your home carrier’s profile side by side.
Provisioning: The behind-the-scenes process of setting up and delivering your eSIM profile to your phone. When you buy a plan, and it appears ready to install, provisioning just happened.
PUK: An unlock code used to recover a SIM that’s been locked after too many wrong PIN entries. Rarely relevant for travel eSIMs, but it’s the term you’d search for if a SIM ever gets PIN-locked.
Q
QR Code: The square barcode you scan to install your eSIM. It carries all the information your phone needs to download the right profile. For Maya, installation is as simple as scanning the QR code (or tapping install in the app) and following the prompts, taking about 2 minutes from start to finish.
R
Regional Plan: A data plan that covers a group of countries in one region. Say, all of Europe or several Asian countries on a single eSIM. Ideal for multi-country adventures, regional plans cover several destinations within a single region, but Maya’s eSIM goes beyond regional limits. It keeps you connected across multiple regions with a single plan.
Roaming: Using your phone’s service outside your home network’s area. Old-fashioned roaming with your home carrier could be shockingly expensive; a travel eSIM gives you local rates instead. (See also Data Roaming for the phone setting you may need to switch on.)
RSP (Remote SIM Provisioning): The industry standard that makes it possible to download a SIM to your phone over the internet instead of inserting a physical card. It’s the foundation on which all eSIMs are built.
S
SIM (Subscriber Identity Module): The component that identifies you to a mobile network and lets your phone connect. Traditionally, a small plastic card; with eSIM, it’s software instead.
SIM Swap: Physically switching one SIM card for another, the old way to change networks when you traveled. eSIMs make this obsolete: you just toggle to a different profile in your settings, no tray-fiddling or lost cards.
SM-DP+: The secure server that stores your eSIM profile and delivers it to your phone when you install. It’s the “vault” your profile is sent from, working invisibly during setup.
Speed Test : A quick check (using an app or website) of how fast your current connection is, in Mbps. Running one is a handy way to confirm that your eSIM is working properly once you arrive.
T
Tethering: See Hotspot. Same idea: sharing your eSIM’s internet with other devices.
Throttling: When your data speed is intentionally slowed, usually after you exceed a fair-use threshold on an unlimited plan. Your connection still works, it’s just slower for a while, and often resets the next day. For typical travel use, you’re unlikely to hit it (see Fair Use Policy).
Tier-1 Carrier: A country’s biggest, most reliable network with the widest coverage. Travel eSIMs that partner with tier-1 carriers give you the strongest signal and best speeds, which is what you want in unfamiliar places.
Top-up: Adding more data or days to an eSIM you already have, instead of buying a whole new one. When a plan runs low or expires, a quick top-up in the app gets you going again, no reinstalling required.
U
UICC: The technical name for a traditional SIM card’s chip. Its eSIM cousin is the eUICC (see above): same job, but built-in and reprogrammable.
Unlimited Data: A plan with no fixed gigabyte cap, so you don’t have to ration your usage, though a fair-use policy may apply to extreme use (see Fair Use Policy). All of Maya’s plans include unlimited data, so you can stream, map, and share freely on a trip.
Unlocked Phone: A phone that isn’t tied to a single carrier and can therefore use other SIMs and eSIMs, including a travel eSIM. An unlocked, eSIM-capable phone is all you need to use Maya. If you bought your phone outright or have finished paying it off, it’s usually unlocked. If unsure, ask your carrier.
V
Validity Period: How long your plan lasts, measured in days (for example, Maya’s 3-, 7-, 14-, or 30-day plans). The clock typically starts when your eSIM first connects to a network at your destination, not when you buy it.
VoIP (Voice over Internet Protocol): Making voice or video calls over the internet instead of a traditional phone line, like WhatsApp, FaceTime, Zoom, or Google Meet. Because most travel eSIMs are data-only, VoIP is how you’ll call home: as long as you have data, you can talk and video-chat for free within those apps.
VoLTE (Voice over LTE): A technology for making regular phone calls over a 4G network with better clarity. It matters mainly for eSIMs that include a phone number; for data-only travel eSIMs, you’ll typically use VoIP apps instead.
VPN (Virtual Private Network): A tool that routes your internet through a secure server elsewhere, hiding your location and protecting your data. Travelers use VPNs for privacy on public Wi-Fi or to access home-country services (such as banking or streaming) that may be blocked abroad. A VPN works right alongside your Maya eSIM.
W
Wi-Fi Calling: Making calls and sending texts over a Wi-Fi connection using your normal phone number instead of the cellular network. Useful as a backup when the signal is weak, though on a data-only travel eSIM, VoIP apps are usually the simpler way to stay in touch.
Z
Zero-rating: When certain apps or services don’t count against your data allowance. It’s a term you’ll occasionally see in plan descriptions; on an unlimited plan, it matters less, since you’re not counting data in the first place.
