eSIM glossary
Every term you will meet while buying a travel eSIM — explained without jargon, each linked to the full guide when you want the details.
APN
The APN (Access Point Name) is the gateway setting that connects your phone to a carrier's data network — usually configured automatically by an eSIM.
Read definition →Carrier lock
A carrier-locked phone only accepts SIMs and eSIMs from the carrier that sold it — it must be unlocked before a travel eSIM will work.
Read definition →Data-only eSIM
Most travel eSIMs are data-only: they provide internet but no phone number, with calls handled by apps or your home SIM.
Read definition →Dual SIM
Dual SIM means running two lines on one phone — typically your home SIM for calls plus a travel eSIM for data.
Read definition →eSIM
An eSIM (embedded SIM) is a digital SIM built into your phone that lets you activate a mobile plan without inserting a physical SIM card.
Read definition →eSIM profile
An eSIM profile is the downloadable carrier configuration — account identity, keys and settings — installed into your phone's eUICC chip.
Read definition →eUICC
The eUICC is the secure hardware chip inside an eSIM-capable device that stores and manages downloadable SIM profiles.
Read definition →Fair-use policy (FUP)
A fair-use policy defines the hidden limits of an "unlimited" plan — usually a daily high-speed allowance followed by reduced speeds.
Read definition →Global eSIM
A global eSIM works in 100+ countries on one plan — the most convenient option for round-the-world routes, usually at a price premium.
Read definition →Hotspot / tethering
Tethering (personal hotspot) shares your phone's mobile data with a laptop or other devices — some travel eSIM plans restrict it.
Read definition →KYC / ID verification
Some countries require identity verification (KYC) before an eSIM can be activated — most travel eSIMs skip it, but local rules vary.
Read definition →Network priority / deprioritization
Travel eSIMs ride on partner networks as roaming traffic, which can be served at lower priority than local customers during congestion.
Read definition →Plan validity
Plan validity is the number of days a travel eSIM plan stays usable — the countdown usually starts at activation, not at purchase.
Read definition →Price per GB
Price per GB divides a plan's cost by its data allowance — the single best number for comparing travel eSIM value.
Read definition →QR code activation
Most travel eSIMs install by scanning a QR code that points your phone to the provider's profile server.
Read definition →Regional eSIM
A regional eSIM covers many countries in one area — like Europe or Asia — on a single plan, ideal for multi-country trips.
Read definition →Roaming
Roaming is using your home carrier's service on a foreign network — convenient, but usually the most expensive way to get data abroad.
Read definition →SM-DP+
SM-DP+ (Subscription Manager Data Preparation) is the secure server that prepares and delivers eSIM profiles to your phone.
Read definition →Throttling
Throttling is when a network deliberately slows your connection speed, typically after you pass a data or fair-use limit.
Read definition →Unlimited data
On travel eSIMs, "unlimited data" almost always means unlimited access with a daily high-speed allowance, then reduced speeds.
Read definition →