eSIM and roaming glossary: carrier terms, phone settings and pass names in plain English

Activation on first connection

On 374 of our 379 plan families, the days start when the eSIM first connects at your destination (our catalog, October 29, 2026). The other 5 (Bosnia and Herzegovina, Mayotte, Suriname) start at installation; check your plan and see not active yet.

Add Cellular Plan

Add Cellular Plan is the iPhone button that adds the eSIM once you scan its QR code (Apple). How to install an eSIM has every step.

EID

The EID is the identification number of the eSIM chip, the eUICC, in your phone.

eSIM

An eSIM is a SIM built into the phone, added by QR code or link instead of a plastic card. Apple calls it “an industry-standard digital SIM built into your iPhone” (Apple); see what is an eSIM.

eSIM activation

Activation turns an installed eSIM into a working line; our plans follow the rule under activation on first connection.

eSIM card

“eSIM card” is another name for an eSIM, and no card is involved.

eSIM profile

An eSIM profile is one downloaded plan on the chip, and Apple says an iPhone can manage “up to eight or more eSIMs” (Apple). The dual SIM guide shows which one carries data.

eSIM Quick Transfer

eSIM Quick Transfer moves your carrier number to another iPhone if the carrier supports it, with both on iOS 18.4 or later (Apple). Apple does not say a third-party travel eSIM moves this way; see transfer an eSIM.

eSIM-only phone

An eSIM-only phone has no SIM tray; do iPhones have SIM cards? lists the models. Apple says US iPhone 14 models and later “can only be activated with an eSIM” (checked on October 29, 2026, Apple).

eUICC

The eUICC is the embedded chip that stores your eSIM profiles, and the EID is its number. The phone list shows which phones have one.

QR code (activation code)

A QR code carries the eSIM plan to your phone, and an iPhone reads it with the Camera app (Apple). Then comes Add Cellular Plan.

Carrier lock

A carrier lock ties a phone to one carrier, so it rejects other carriers’ SIMs and eSIMs. Apple says “Only your current carrier can unlock your iPhone” (Apple); see the carrier-locked guide.

MNO

An MNO, or mobile network operator, owns the radio network its customers use, while an MVNO rents one.

MVNO

An MVNO, or mobile virtual network operator, sells plans over another carrier’s network. Smaller carriers’ roaming is in the roaming hub.

“No SIM restrictions”

On an iPhone, “No SIM restrictions” next to Carrier Lock means the phone is unlocked (Apple). If you don’t see it, Apple says to contact your carrier; Is my phone unlocked? has the check.

Postpaid

A postpaid plan bills you after you use the service. AT&T sells its International Day Pass on postpaid plans, and its Prepaid pages do not mention one (AT&T roaming).

Prepaid

A prepaid plan is paid for before you use it; our travel eSIMs are prepaid, and most are data only. AT&T Prepaid’s International Travel Add-On is $40 for seven days with talk, text and 5GB of data (checked on October 29, 2026, AT&T Prepaid).

SIM lock

“SIM lock” is another name for a carrier lock. AT&T’s page says that if Carrier Lock “says SIM locked, your device is locked” (AT&T); see the carrier-locked guide.

SIM PIN

Neither a SIM PIN, which guards the SIM itself, nor your screen passcode decides which carriers the phone accepts (carrier lock vs SIM PIN).

Unlocked phone

An unlocked phone takes a SIM or eSIM from any compatible carrier, a travel eSIM included. Check yours: Is my phone unlocked?

APN

The APN, or access point name, helps your carrier “find the right IP address for your phone”, Google says (Google). Our plan pages say whether it sets itself or needs entering by hand (full bars, no data).

Cellular at sea

Cellular at sea is AT&T’s name for a ship’s own maritime network; our eSIM works in port, not there. AT&T’s Day Pass covers listed ships at $20 a day per line (checked on October 29, 2026, AT&T); see phone on a cruise.

Data roaming

Data roaming is the phone setting that Apple says “permits internet access over a cellular data network” where your carrier’s network doesn’t reach (Apple). A roaming pass is a separate carrier product: AT&T’s and Verizon’s can start with a call or text, even with data roaming off.

Dual SIM

Dual SIM means one phone runs two lines, and Apple says an iPhone “can use one cellular data network at a time” (Apple). With a travel eSIM, your US number stays the voice line and the eSIM carries data: see dual SIM setup.

Hotspot

A hotspot shares your phone’s cellular data with another device; for our plans, the plan doesn’t state a hotspot rule — check the plan page. T-Mobile says its International Passes include high-speed data “you can use as a mobile hotspot” (checked on October 29, 2026, T-Mobile).

Pocket Wi-Fi

A pocket Wi-Fi is a router you rent for the trip, one more device to charge and return. The Japan guide weighs it against an eSIM.

Wi-Fi calling

Wi-Fi calling places calls and texts over Wi-Fi instead of the cellular network (dual SIM guide). Abroad, AT&T says its Wi-Fi calling is “charged like cellular calling” (AT&T), and Verizon says it “isn’t included with TravelPass” (Verizon).

Global Day Pass (Spectrum Mobile)

Spectrum’s Global Day Pass is $10 for 24 hours with 1 GB of high-speed data, then reduced speed (checked on October 29, 2026, Spectrum). It is $5 in Canada and Mexico and renews daily while it is on.

Global Pass (Visible)

On base Visible, Global Pass is $10 a day with talk, text and 2GB of data in 140 countries (checked on October 29, 2026, Visible). Once enabled, it runs every day you are away.

Global Travel Pass (Xfinity Mobile)

Xfinity’s Global Travel Pass is $10 a day per line, with 5 GB of high-speed data, then 3G speeds (checked on October 29, 2026, Xfinity). It does not cover cruises or flights.

International Day Pass (AT&T)

AT&T’s International Day Pass is $12 a day per line on eligible postpaid plans in 210+ destinations; extra lines used that day are $6 each. Its 24 hours start with your first data use, text sent, or call made or accepted there (checked on October 29, 2026, AT&T).

International Pass (T-Mobile)

T-Mobile’s International Pass costs $10 (2GB, up to 24 hours), $50 (15GB, up to 10 days) or $75 (30GB, 30 days). You pick the start date in T-Life or My T-Mobile, and with no date it starts at once (checked on October 29, 2026, T-Mobile).

Minternational Pass (Mint Mobile)

Mint’s Minternational Pass works in 180+ countries: 1 day with 1GB for $5, 3 days with 3GB for $10, 10 days with 10GB for $20. Mint says the passes do not work in Canada, because of its Free Canada Roaming (checked on October 29, 2026, Mint, Mint Canada).

Passport (Cricket Wireless)

Cricket’s daily Passport is $10 a day per line, charged for every 24 hours of use until you cancel it. It includes no hotspot, partner speed may drop to 2G, and a 5-day pass is $25 for 5GB (checked on October 29, 2026, Cricket).

Simple Global (T-Mobile)

Simple Global is not a pass: it is T-Mobile’s name for its 215+ countries and destinations where qualifying plans work with no setup. Essentials has no data abroad without a pass (checked on October 29, 2026, T-Mobile).

TravelPass (Verizon)

Verizon’s TravelPass is $12 a day, $6 in Mexico and Canada, with 5 GB of high-speed data per session, then 3G. A call made or answered, a text sent or data use starts a 24-hour session, background data included (checked on October 29, 2026, Verizon).

50% usage rule (Mexico and Canada)

If more than 50% of your talk, text or data usage in a 60-day period is abroad, Verizon says it “may be removed or limited”. Verizon prints it two ways, Canada or Mexico and countries other than the US, so check your plan (checked on October 29, 2026, Verizon). Cricket’s rule covers Canada only: usage there must “stay under 50% of your total usage in a 3-month period” (Cricket).

Bill Protection

Google Fi Flexible charges $10 for each GB until Bill Protection kicks in at a threshold set by the number of people on your plan. After that, “data is free for the rest of your billing cycle”, though slower above 15 GB (checked on October 30, 2026, Google Fi plans).

Daily limit plan (X GB/day at full speed, then reduced to Y)

A daily-limit plan gives a fixed amount of full-speed data each day, then a lower speed. We print it as “Unlimited — X GB/day at full speed, then reduced to Y”, beside the price and with no asterisk. All 754 such packages in our storefront data state both numbers (our count, October 30, 2026); daily limits explained says why.

Reduced speed after high-speed data (256Kbps and others)

Reduced speed follows a plan’s or pass’s high-speed data: T-Mobile Experience More gives up to 5GB abroad, then up to 256Kbps. Verizon’s TravelPass and Xfinity’s Global Travel Pass drop to 3G after 5 GB, and Cricket says partner speed on Passport may drop to 2G.

Next step: Is my phone unlocked? and Does my phone support eSIM?, then the roaming table.

Sources checked: Apple: 118669, 109357, 118227, 109316, 109037, 109317; Google Pixel · AT&T: Day Pass, at sea, Prepaid, unlock; Verizon: TravelPass, plan information; T-Mobile: roaming, pass · Mint Mobile, Visible, Xfinity Mobile, Spectrum Mobile, Cricket (roaming, Canada), Google Fi plans.