eSIM
A digital SIM card built into the phone: the plan installs online, with no physical card to slot in. It is the GSMA standard gradually replacing the classic SIM card.
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eSIMrat
eSIMrateSIM glossary
EID, ICCID, APN, fair use, roaming: the vocabulary of the eSIM explained plainly, with what each term changes when you pick a plan. 107 terms, no untranslated jargon.
The 5 terms to know before buying an eSIM
Alphabetical index (107 terms)
2G and 3G (networks being switched off)4G / LTE5G (NSA and SA)5G RedCapActivating an eSIMActivation QR codeActivation windowAPNAuto-renewalCarrier unlockingCloud SIM and soft SIMCoverage mapCruise / maritime eSIMData planData roamingData rolloverData usageData-only eSIMDay passDeleting an eSIMDSDS (dual SIM dual standby)Dual SIMEIDeIM and IPA (IoT eSIM)eSIMeSIM backup and reissueeSIM compatible deviceeSIM customer supporteSIM for digital nomadseSIM for laptopseSIM for smartwatcheseSIM management platformeSIM profileeSIM Quick TransfereUICCFair use policyForm factor (2FF, 3FF, 4FF)Frequency bandGlobal eSIMGSMAGSMA specifications (SGP.21, SGP.22, SGP.31, SGP.32)Host operator (partner network)ICCIDIMEIIMEI lockingIMSIIn-flight connectivityInstalling an eSIMInstant eSIMIoT (Internet of Things)iSIMKYC / eKYC (identity check)Latency (ping)Local breakoutLocal eSIMLPA (Local Profile Assistant)Manual activation (no QR code)MB and GB (megabyte, gigabyte)MFF2 (and MFF4)MNO (network operator)MSISDNMulti-IMSIMulti-network accessMulti-profile deviceMVNO (virtual operator)National roamingNetwork attachNetwork coverageNetwork slicingNumber portabilityOTA (over-the-air)Pay-as-you-go billingPhysical SIM card (pSIM)PIN and PUK codesPlan validityPLMN, MCC and MNCPrepaid eSIMPrice per GBPrimary and secondary lineReceiving texts abroadRefund policyRegional eSIMRoam like at home (EU)Roaming agreementRoaming hub (wholesale roaming)Roaming steeringRSP (remote provisioning)Satellite connectivity (Direct-to-Cell)SM-DP+SM-DSSpeed (Mbit/s)Standalone eSIMSubscription managementTethering (hotspot)Throttling and deprioritisationTop-upTourist eSIM (temporary)Transferring an eSIMUICCUnlimited dataUser equipment (UE)Virtual numberVirtual SIMVoLTEVoNRVPN abroadWi-Fi calling (VoWiFi)
The basics
The terms to know before anything else: the eSIM card, its identifiers, your phone.
Physical SIM card (pSIM)
The classic removable chip card, in nano format on recent phones. It stores a single carrier profile, where an eSIM can store several.
Read the full entryeSIM profile
The whole set of a carrier's data (identifiers, keys, network settings) downloaded into the eSIM chip. A phone can store several profiles and keep one or two active at a time.
EID
The unique 32-digit identifier of your phone's eSIM chip. Some providers ask for it to check compatibility or to prepare an eSIM.
Read the full entryIMEI
The unique identification number of the handset itself (15 digits), shown by dialling *#06#. Not to be confused with the EID (the eSIM chip) or the ICCID (the profile).
Read the full entryICCID
The serial number of a SIM or eSIM profile (19 or 20 digits, starting with 89). Every installed eSIM has its own: it is what identifies your plan at the carrier.
Read the full entryeUICC
The physical chip soldered into the phone that hosts the eSIM profiles. It is what makes downloading, storing and switching carrier possible without a card.
Read the full entryiSIM
The eSIM's next step: the SIM function sits directly inside the phone's processor, with no dedicated chip. Still rare on consumer smartphones in 2026.
Dual SIM
A phone's ability to use two lines at once, for example your usual SIM and a travel eSIM. Ideal for keeping your number while browsing on a local plan.
Read the full entryDSDS (dual SIM dual standby)
The most common dual SIM mode: both lines are reachable, but only one carries data at a time. That is what iPhones and most eSIM-capable Android phones do.
Activation QR code
The QR code you get when buying an eSIM: scanning it triggers the profile download into the phone. It carries the server address (SM-DP+) and the activation code.
Read the full entryeSIM compatible device
A phone, watch or tablet fitted with a eUICC chip whose model (and sometimes region of purchase) allows eSIM. Check your model before buying a plan.
See the dedicated pageMB and GB (megabyte, gigabyte)
Units of data volume: 1 GB = 1,000 MB. An hour of HD video uses about 1 GB, an hour of GPS about 10 MB.
Data usage
The volume of mobile data you use, per day or per month. It is the first thing to estimate when picking the size of your eSIM plan.
See the dedicated pageVirtual SIM
Another common name for the eSIM: a dematerialised SIM card, installed online. The term sometimes also covers app-based virtual numbers, which are a different product.
Read the full entryData plan
A volume of data (in GB) valid for a set period. It is the base product of the travel eSIM: no subscription, one volume, one duration, one price.
eSIM for smartwatches
Cellular watches (Apple Watch, Galaxy Watch…) carry an eSIM so they work without the phone. The option depends on your own carrier, not on travel eSIM providers.
Read the full entryeSIM for laptops
Some laptops (Surface, ThinkPad, Dell…) include an eSIM: mobile internet without tethering. Data-only travel eSIMs work on them when the model supports it.
Multi-profile device
An eSIM-capable phone can store several profiles (5 to 20 depending on the model) and switch between them in the settings. Only one or two are active at a time.
Buying and comparing
The vocabulary of the offers and of the small print, so you pick your plan knowing what you are getting.
Local eSIM
An eSIM plan valid in a single country. Usually the best price per GB, as long as you do not cross a border during the trip.
Regional eSIM
An eSIM plan covering a zone of several countries (Europe, Asia, the Americas). Handy for a multi-country route, often slightly pricier per GB than a local eSIM.
Global eSIM
An eSIM plan covering more than 100 countries. Maximum flexibility, but almost always the highest price per GB: keep it for round-the-world trips and multiple stopovers.
Data-only eSIM
Most travel eSIMs: data, but no number for classic calls or texts. WhatsApp, FaceTime and the like work normally.
Prepaid eSIM
A plan paid once, with no contract or subscription: when the volume or the period runs out, the connection stops (or you top up). The standard travel eSIM model.
Unlimited data
A plan with no advertised volume cap, but almost always a hidden limit: past a daily volume, the speed drops. Read the fair use policy.
Fair use policy
The conditions framing an “unlimited” plan: the daily threshold past which speed drops, forbidden uses (tethering, sometimes), and so on. The most important small print of any unlimited offer.
Read the full entryThrottling and deprioritisation
Speed reduction by the carrier: after a data threshold (throttling) or when the network is congested (deprioritisation). A plan throttled to 512 kbit/s still handles messaging, not video.
Plan validity
The lifespan of the plan (7, 15, 30 days…), counted in general from activation or from the first connection. Data left or not, the plan expires at the end.
Activation window
At some providers, the eSIM must be installed or activated within a set period after purchase. Check it if you buy long before departure.
Auto-renewal
An option that automatically buys the plan again when it expires or runs out. Handy on a long trip, a trap if you forget to switch it off on your return.
Data rollover
A mechanism carrying unused GB over to the next period when you top up. Rare on travel eSIMs: check before counting on it.
Top-up
Buying more data or more days on an eSIM already installed, usually from the provider's app, without reinstalling a profile. Often pricier per GB than the initial plan.
Price per GB
The plan price divided by its volume: the only indicator that lets you compare offers of different sizes. It is the basis of every esimrat comparison.
KYC / eKYC (identity check)
A legal requirement in some countries (Japan, Singapore, the UAE…): showing a passport to activate a local eSIM. International travel eSIMs usually escape it.
MVNO (virtual operator)
An operator without its own network, renting that of an infrastructure operator. Most travel eSIM providers are global MVNOs.
Read the full entryMNO (network operator)
An operator that owns its mobile network (masts, spectrum). Your travel eSIM always ends up connecting to a local MNO's network.
Host operator (partner network)
The local network your travel eSIM actually connects to in the country you visit. A tier-1 network (the main national operator) gives the best coverage: a comparison criterion in its own right.
Refund policy
The terms for refunding an eSIM: most providers only refund uninstalled eSIMs or proven technical faults. Read it before buying.
Instant eSIM
An eSIM delivered right after payment, by email or in the app. That is the market standard: be wary of offers imposing a delay or a manual review.
Tourist eSIM (temporary)
A short plan (5 to 30 days) designed for a stay, with no local contract or commitment. As opposed to local subscription SIMs, which often require ID on the spot.
Day pass
A formula billed per day of use, offered by some carriers and providers. Worth it for occasional use, quickly pricier than a per-GB plan past a few consecutive days.
Pay-as-you-go billing
Paying for the volume actually used, with no predefined plan. Transparent on paper, but the price per GB is usually higher than an equivalent prepaid plan.
eSIM customer support
The provider's support (chat, email), crucial when the install stalls on arrival. Its availability (24/7 or not) and its responsiveness are comparison criteria just like price.
Coverage map
The map an operator publishes to show its service areas. A marketing document above all: real indoor or rural coverage is often more modest.
Standalone eSIM
An eSIM sold independently of any existing subscription, unrelated to your usual carrier. That is the model of nearly every travel eSIM.
Multi-network access
An eSIM's ability to connect to several local networks in the same country, switching according to coverage. A real plus in rural areas or across multiple regions.
Installing and activating
Everything that happens between the purchase and the connection: install, activation, transfer.
Installing an eSIM
Downloading the eSIM profile into the phone, by QR code or manual entry. Best done on wifi, before departure; installing does not necessarily start the plan.
Read the full entryActivating an eSIM
Making the eSIM line active so it connects to the network. Depending on the provider, activation starts the plan's validity: do it at the right moment.
See the dedicated pageDeleting an eSIM
Erasing the eSIM profile from the phone. Careful: on most prepaid eSIMs, a deleted profile cannot be reinstalled, even if the plan was still running.
Transferring an eSIM
Moving an eSIM profile to a new phone. Not every provider allows it: some require a new eSIM, others a simple transfer from the app.
Read the full entryeSIM Quick Transfer
An Apple (and recent Android) feature that moves the SIM or eSIM from an old phone to a new one without going through the carrier. Supported by some carriers only.
See the dedicated pageManual activation (no QR code)
Installing an eSIM by typing the SM-DP+ address and the activation code by hand, when scanning the QR code is not possible (a single device at hand, for instance).
See the dedicated pageAPN
The access point name: the setting that tells your phone which way to go to reach the internet. With most modern eSIMs it configures itself.
Read the full entryPIN and PUK codes
The PIN locks the SIM at power-on, the PUK unlocks it after 3 wrong PINs. Travel eSIMs almost never impose either.
Read the full entryPrimary and secondary line
On a dual SIM phone, you choose which line carries calls, texts and above all data. When travelling: data on the local eSIM, calls and texts on your usual line.
Carrier unlocking
A locked phone only accepts SIMs from the carrier that sold it, eSIMs included. It has to be unlocked to use a travel eSIM; carriers do it free on request.
Read the full entryeSIM backup and reissue
If the phone is lost or reset, an eSIM does not come back on its own: depending on the provider, the profile is reissued through the app or support. Check that policy before a long trip.
On the road
Roaming, tethering, coverage: the terms that matter once you are there.
Data roaming
Using the internet through a foreign network with your usual SIM. Included across Europe on European plans, it can cost a fortune elsewhere: that is the problem the travel eSIM solves.
Read the full entryRoam like at home (EU)
The European rule: your plan works across the EU at no extra cost, within a fair use limit. Outside the EU (Switzerland, the UK depending on the offer…), check your contract.
Tethering (hotspot)
Turning the phone into a wifi access point to connect a laptop or another device. Most travel eSIMs allow it; some unlimited offers restrict it.
Read the full entryWi-Fi calling (VoWiFi)
Making calls on your usual line over wifi, with no mobile network. Abroad, it keeps you reachable on your home number without paying voice roaming.
Read the full entryCruise / maritime eSIM
At sea, ships relay mobile signal by satellite, outside any land plan and at very high rates. Ordinary eSIMs do not work there: dedicated cruise plans exist.
In-flight connectivity
In the air, flight mode is mandatory; some airlines sell onboard wifi. A travel eSIM connects on the ground, not at altitude: install it before, activate it on arrival.
Network coverage
The area where an operator actually has signal, and in which technology (4G, 5G). At equal eSIM quality, the local host operator is what makes the difference on the ground.
Read the full entryRoaming steering
The technique by which a provider pushes your eSIM towards its preferred partner network, even when another one has better signal. Selecting the network manually sometimes works around it.
Number portability
Keeping your number when changing carrier, through a portability code. Unrelated to the travel eSIM: your usual line stays intact, the eSIM is added next to it.
Receiving texts abroad
With a data-only eSIM, texts (bank codes included) still land on your usual line: keep it active in roaming, receiving a text is free almost everywhere.
VoLTE
Voice carried over the 4G network instead of the old 2G/3G ones. Essential in countries that have switched 2G/3G off: a phone without VoLTE can no longer make calls there.
Read the full entryVPN abroad
An encrypted tunnel between your phone and a remote server. Travelling, it secures public wifi and reaches services blocked in some countries (China in particular); it slightly increases data use.
Virtual number
A phone number provided by an app, with no SIM card attached. A useful companion to a data-only eSIM for receiving local calls or texts, but often refused by banks.
Read the full entryeSIM for digital nomads
Long-stay, multi-country use: rechargeable global plans, large volumes, daily video calls and tethering. What matters: price per GB, fair use and top-up policy.
Satellite connectivity (Direct-to-Cell)
Technology connecting a standard phone straight to a satellite, outside any ground mast (Starlink Direct to Cell, 3GPP NTN standard). Limited to messaging at a few carriers today, it will complement the eSIM in white zones.
Read the full entryAdvanced technical
Under the eSIM's bonnet: the standards, servers and identifiers carriers work with.
SM-DP+
The carrier server that prepares and delivers eSIM profiles. Its address sits inside the QR code; you type it by hand during a manual activation.
Read the full entrySM-DS
The discovery server of the eSIM standard: it lets the phone find out on its own that a profile is waiting, without scanning a QR code.
LPA (Local Profile Assistant)
The phone software that downloads, activates and deletes eSIM profiles. It is what works behind your phone's “Add eSIM” screen.
RSP (remote provisioning)
Remote SIM Provisioning: the GSMA architecture that loads a carrier profile remotely into a eUICC chip. The technical heart of the eSIM.
GSMA
The worldwide association of mobile operators. It publishes the eSIM specifications (SGP.22 for consumers), certifies the players of the ecosystem (SAS certification) and runs the MWC in Barcelona.
GSMA specifications (SGP.21, SGP.22, SGP.31, SGP.32)
The family of standards defining the eSIM: SGP.21/22 for consumer devices (smartphones), SGP.31/32 for IoT, SGP.02 for the older M2M world. “SGP.22 compliant” means compatible with every carrier.
eIM and IPA (IoT eSIM)
The two new roles of the SGP.32 IoT standard: the eIM orchestrates the eSIMs of connected-object fleets remotely, the IPA is the assistant embedded in the device. The IoT equivalent of your smartphone's LPA.
MFF2 (and MFF4)
The physical format of the soldered eSIM chip (about 6 x 5 mm), with a more compact MFF4 variant. It is the form factor succeeding the 2FF (mini), 3FF (micro) and 4FF (nano) cards.
UICC
The technical name of the removable SIM smart card. The eUICC is its embedded, reprogrammable version, soldered into the device.
Form factor (2FF, 3FF, 4FF)
The physical size of a SIM card: mini (2FF), micro (3FF), nano (4FF). The eSIM (MFF2) removes the question: nothing left to cut out or slot in.
IMSI
The international mobile subscriber identity, stored in the SIM profile. It is what the network checks at every connection; it also determines your “home” country in roaming.
Read the full entryMulti-IMSI
Technology embedding several subscriber identities in a single profile: the eSIM switches to the most favourable IMSI for the country. Used by several global providers.
MSISDN
The phone number as the network understands it (the one people dial to reach you). A data-only eSIM assigns none, or a technical number unusable for calls.
Read the full entryOTA (over-the-air)
Any update sent over the air, with nothing to do by hand: eSIM profiles, carrier settings, system updates. The eSIM is 100% OTA.
Local breakout
An architecture where your internet traffic exits directly in the country you visit instead of going back through the provider's home country. The result: lower latency on the spot.
Frequency band
The radio ranges used by mobile networks (700 MHz, 3.5 GHz…). A phone bought in Europe covers the European bands; check compatibility for some distant countries.
4G / LTE
The fourth generation of mobile network, plenty for every travel use (GPS, streaming, video calls). It is the backbone of most travel eSIMs.
5G (NSA and SA)
The fifth generation of mobile network. NSA: 5G leaning on a 4G core (the common case); SA: standalone 5G. Many travel eSIMs include 5G where the host network offers it.
VoNR
Voice over New Radio: voice calls carried by standalone (SA) 5G, as VoLTE does on 4G. Still marginal, carriers included.
Latency (ping)
The round-trip time of a data packet, in milliseconds. High latency (traffic routed back through Europe, for instance) shows in video calls and browsing, not in a download.
Speed (Mbit/s)
The speed of the connection, in megabits per second. 5 Mbit/s is enough for HD video; the throttled speeds advertised (512 kbit/s, 1 Mbit/s) should be read against that scale.
IMEI locking
Tying a line to one specific device, identified by its IMEI. Some countries or carriers use it against theft; rare but real on local SIMs in a few countries.
Cloud SIM and soft SIM
Approaches with no dedicated chip: the SIM profile lives in software (soft SIM) or on remote servers (cloud SIM, used by pocket hotspots). Outside the GSMA standard, unlike the eSIM.
Network attach
The authentication of your SIM on a visited network: the local network queries your home carrier before letting you in. That is what happens during those “Searching for network…” seconds on landing.
Roaming agreement
A contract between two operators letting the customers of one use the other's network. The coverage of a global eSIM is the sum of its provider's roaming agreements.
Roaming hub (wholesale roaming)
A platform aggregating hundreds of roaming agreements and reselling them to MVNOs. These hubs are how a small eSIM provider can cover 190 countries without negotiating country by country.
National roaming
Using a competitor's network inside your own country, in areas your own does not cover. Not to be confused with the traveller's international roaming.
eSIM management platform
The system (SM-DP+, portal, app) a provider uses to create, deliver and track its eSIM profiles. Invisible to you, but its reliability is the difference between a QR code that works and a support ticket.
Subscription management
The generic name of the infrastructure handling the eSIM profile lifecycle remotely (SM-DP+ and SM-DS servers). The plumbing standardised by the GSMA behind every installation.
Network slicing
The ability of standalone 5G to carve one physical network into virtual networks with guaranteed performance. Still no concrete impact on travel eSIMs in 2026.
Read the full entryUser equipment (UE)
The standards term for any device connecting to a mobile network: phone, watch, laptop, sensor. You will meet it in carrier technical documentation.
IoT (Internet of Things)
Objects connected to the mobile network: trackers, cars, sensors. The eSIM is used there massively (SGP.32 standard); that is where the technology in your phone comes from.
PLMN, MCC and MNC
The identity of a mobile network: country code (MCC) plus operator code (MNC) form the PLMN, visible in manual network selection. Useful to check which host operator your eSIM is really on.
5G RedCap
A lighter version of 5G (Release 17) designed for watches and connected objects: less speed, less power draw. It will reach eSIM wearables over the coming years.
2G and 3G (networks being switched off)
The older network generations, being switched off in many countries (2G already gone in Switzerland, 3G in France by 2028). For travellers: VoLTE becomes essential for calls.
A term missing? Write to us through the contact page, and we will add it to the glossary.
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