An eSIM is a SIM chip built into your phone instead of a removable plastic card. A mobile plan is downloaded to that chip as a profile, usually by scanning a QR code over Wi-Fi, and you choose which profiles are active in your settings. eSIM is a GSMA standard used by networks worldwide.
What is an eSIM?
An eSIM is a SIM chip built into the phone, called an eUICC, instead of a removable card. Because it is embedded, there is no tray to open and no plastic to lose. The chip holds your mobile plans as digital profiles, and eSIM is a GSMA standard used by networks worldwide.
Apple describes an eSIM as an industry-standard digital SIM built into the iPhone that removes the need for a physical SIM card. Samsung describes it as an embedded version of a physical SIM card within the device that connects to the carrier's network without a physical card and is activated with the carrier account details.
The chip does the same job as the chip inside a plastic SIM: it identifies your line to the network. The difference is that you never handle it. Instead of swapping cards, you add or remove plans in software. A plan stored on the chip is called a profile, and it contains the details your phone needs to connect, such as the network identity and the settings for calls and data.
Because the chip cannot be removed, a lost phone's eSIM cannot be taken out and used in another handset. A plastic SIM can be moved to a spare phone; an eSIM cannot.
How an eSIM works inside your phone
A plan is downloaded to the chip as a profile and activated with your carrier account details. The download needs an internet connection, so do it over Wi-Fi before you travel. Once installed, the profile stays on the phone until you delete it.
The technical side is set out by the GSMA. SGP.21 sets out the Remote SIM Provisioning architecture for consumer eSIM, and SGP.22 is the consumer Remote SIM Provisioning specification, with version 3.1 dated 1 December 2023 listed as active. For connected devices there is a separate specification, SGP.32, version 1.3 dated 22 May 2026 listed as active.
In practice, the phone contacts a provisioning server, receives the profile over the network and writes it to the eUICC. The GSMA says TLS is mandated in its consumer remote provisioning protocol, and an eSIM certification process exists to address compromised provisioning servers (SM-DP+) or eUICC chips.
You do not manage any of this by hand. You choose to add a plan, supply the carrier details, and the phone does the rest.
How to install an eSIM: QR code, code or app
Most eSIMs are installed by scanning a QR code over Wi-Fi, though some phones accept an activation code or a carrier push. The menus differ by brand, so follow the path for your handset. Install before you fly, while you still have reliable Wi-Fi.
On iPhone, an eSIM can be added with a carrier QR code by tapping Use QR code on the Set Up Cellular screen, or after setup by scanning the code with the Camera app. On iOS 17.4 or later you can press and hold a QR code in an email or browser and tap Add eSIM.
On Google Pixel, add an eSIM in Settings > Network & internet > SIMs > Add SIM > Set up an eSIM, or tap Download SIM during phone setup.
On Samsung Galaxy phones, add an eSIM in Settings > Connections > SIM manager > Add eSIM, using a carrier QR code, the carrier discovery server or a carrier push notification, followed by a restart. Samsung UK says Galaxy users can also add a plan with an activation code (Add using activation code) where the provider offers it.
Our step by step guide on how to install an eSIM covers the screens for each brand.
How many eSIMs a phone can hold
A phone can store several eSIM profiles, but only a limited number can be active at once. Apple says iPhone can manage up to eight or more eSIMs. With Dual SIM on iPhone, two numbers can be active at once for calls and messages, but only one cellular data network at a time.
On iPhone, Dual SIM with an eSIM requires iPhone XS, iPhone XS Max, iPhone XR or later. iPhone 13 models and later support Dual SIM with two eSIMs, so no plastic card is needed at all.
On Pixel, Pixel 3a and later can use one physical SIM and one eSIM together. Using two eSIM profiles at once needs a Pixel 7 or later and carrier support.
Stored profiles are not the same as active ones. You can keep a travel profile on the phone for months and switch it on only when you land. If you want to know which line is doing what, the EID and IMEI in your settings help identify each one; our guide to the EID number explains where to find it.
Which phones support eSIM
iPhone XS, XS Max and XR (2018) and later support eSIM, and iPhone 14 models or later purchased in the United States can only be activated with an eSIM. Google Pixel 3a and later and recent Samsung Galaxy phones support eSIM, depending on model and country.
Apple's September 2018 iPhone XR announcement introduced Dual SIM through a nano-SIM and a digital eSIM, delivered by a software update later that autumn. Apple's September 2022 iPhone 14 announcement said iPhone 14 and iPhone 14 Plus remove the SIM tray for US models.
On Android, Pixel 3a and later can use one physical SIM and one eSIM together. In the US, Pixel 10 and later (except Pixel 10 Pro Fold) can only use an eSIM. Samsung Galaxy phones support eSIM through SIM manager, and Galaxy phones can transfer an eSIM from another Galaxy via SIM manager > Add eSIM > Transfer SIM from another phone, and can convert a physical SIM with Convert to eSIM. Wi-Fi-only tablets do not support eSIM.
Support depends on the model and the market it was sold in, so check your exact handset with our guide to is my phone eSIM compatible.
eSIM vs a physical SIM
An eSIM is built in and managed in software; a physical SIM is a removable card you can move between phones. Both identify your line to the network. The practical differences are swapping, replacement and travel.
A plastic SIM can be taken out and put into a spare handset, which is useful if a phone breaks. An eSIM cannot be removed, so it cannot be moved that way. Instead, iPhone offers eSIM Quick Transfer: both iPhones must be on iOS 18.4 or later, signed in with an Apple Account, with Bluetooth on and close together, and the carrier must support it. With iOS 26 or later more than one number can be transferred. The old SIM is deactivated when the new plan activates.
For travel, an eSIM means you can add a local data plan without hunting for a shop or opening the tray. A physical SIM means a trip to a counter and a new card. Our comparison of eSIM vs physical SIM sets the two side by side.
Using an eSIM for travel and keeping your number
A travel eSIM is data only, so keep your home SIM in the phone for calls, texts and bank codes, and turn off data roaming on it. Install the travel profile before you fly, then switch it on when you land.
Apple says a supported iPhone can have two eSIMs active at once while travelling, so you can keep your home number and add a travel line. If you use only the travel eSIM, FaceTime and iMessage keep working on your home number. To use a local or worldwide travel eSIM, Apple says the iPhone must not be locked to a carrier. The data line can be chosen in Settings > Cellular > Cellular Data.
On iOS 26 or later, iPhone shows a Turn On Travel eSIM prompt on arrival and, depending on country or region, switches back to the home SIM automatically on return.
Slashtel eSIMs follow the same pattern: data only, with no local phone number and no calls or SMS, though WhatsApp and other internet calls work over the data. The eSIM is bought online with an email address and a card, Apple Pay or Google Pay, and the QR code arrives by email within minutes. Someone else can buy it and enter the traveller's email, so the code goes straight to the person who will use it. Validity starts when the eSIM first connects at the destination, so it can be bought and installed at home before the flight. The network is chosen automatically and cannot be picked by hand, and more data can be added to the same eSIM later with no new QR code. The phone must be unlocked and eSIM compatible. If you are unsure how much you need, the data calculator helps, and you can browse destinations to see what is covered. Slashtel also sells mobile top-ups to more than 100 countries, delivered in minutes, which keep a prepaid home line active. Support is on WhatsApp and email, 7 days a week.
Is an eSIM secure?
eSIM security rests on GSMA specifications and accreditation. The GSMA runs two security accreditation schemes: SAS-UP for UICC/eUICC production sites and SAS-SM for subscription management sites, and each certification involves an on-site audit by GSMA-appointed auditors.
The GSMA also says TLS is mandated in its consumer remote provisioning protocol, and an eSIM certification process exists to address compromised provisioning servers (SM-DP+) or eUICC chips.
For you as a user, the practical points are simple. A profile is tied to the phone's embedded chip, so it cannot be lifted out and dropped into another handset. The EID identifies the chip: on iPhone it is shown in Settings > General > About (you may need to scroll down), alongside the IMEI and ICCID, and it is also printed on the barcode label of the original packaging. Samsung says dialling *#06# shows the phone's IMEI and serial number, where supported by the carrier, and the EID is shown in Settings > About phone > Status or on the phone's box.
Treat the QR code like a password. Anyone who scans it first may install the plan.
Common eSIM questions answered
The questions below cover the points readers ask most: what an eSIM card actually is, how does an eSIM work day to day, whether a phone supports one, and whether an eSIM for travel is worth the setup.
A few short answers:
- An eSIM card is not a card at all; it is the embedded chip plus the profile downloaded to it.
- How an eSIM works is mostly invisible: the phone contacts a provisioning server and writes the profile to the chip.
- Does my phone support eSIM depends on model and market, so check the settings or the manufacturer's specification.
- An eSIM for travel is data only, installed before departure and switched on at the destination.
More detail on each is in the FAQ below.
Sources
Checked 24 October 2026. Rules and dates can change, so check the official pages before you rely on them.
- https://support.apple.com/en-us/118669
- https://www.samsung.com/esim-support/
- https://www.gsma.com/esim/technical-papers/esim-specification/
- https://www.gsma.com/solutions-and-impact/technologies/esim/wp-content/uploads/2024/09/SGP.21-v2.6.pdf
- https://www.gsma.com/solutions-and-impact/technologies/esim/expanding-the-esim-ecosystem/
- https://www.gsma.com/solutions-and-impact/technologies/esim/security-analysis-of-the-consumer-remote-sim-provisioning-protocol/
- https://support.apple.com/en-us/109317
- https://www.apple.com/newsroom/2018/09/apple-introduces-iphone-xr/
- https://www.apple.com/newsroom/2022/09/apple-introduces-iphone-14-and-iphone-14-plus/
- https://support.apple.com/en-us/109357
- https://support.google.com/pixelphone/answer/16115470?hl=en
- https://support.google.com/pixelphone/answer/9449293?hl=en
- https://www.samsung.com/uk/support/mobile-devices/how-to-use-an-esim-with-your-galaxy-phone/
- https://support.apple.com/en-us/108037
- https://www.samsung.com/us/support/answer/ANS10002504/
- https://support.apple.com/en-us/118227
Questions, answered
What is an eSIM in simple terms?
An eSIM is a SIM chip built into your phone instead of a removable plastic card. Your mobile plan is downloaded to the chip as a profile, usually by scanning a QR code over Wi-Fi, and you choose which profiles are active in your settings.
How does an eSIM work without a card?
The phone contacts a provisioning server and downloads the plan to the embedded chip, called an eUICC. The GSMA sets out the architecture in SGP.21 and the consumer specification in SGP.22, with version 3.1 dated 1 December 2023 listed as active.
Is an eSIM card the same as a normal SIM?
No. A normal SIM is a removable card you can move between phones. An eSIM card is the embedded chip plus the profile on it, so it cannot be taken out and used in another handset.
Does my phone support eSIM?
iPhone XS, XS Max and XR and later support eSIM, as do Google Pixel 3a and later and recent Samsung Galaxy phones, depending on model and country. Check your exact handset in its settings or the manufacturer's specification.
How do I install an eSIM on iPhone?
Tap Use QR code on the Set Up Cellular screen and scan the carrier code, or scan it later with the Camera app. On iOS 17.4 or later you can press and hold a QR code in an email or browser and tap Add eSIM.
How do I install an eSIM on Samsung or Pixel?
On Galaxy phones go to Settings > Connections > SIM manager > Add eSIM, then restart. On Pixel go to Settings > Network & internet > SIMs > Add SIM > Set up an eSIM.
How many eSIMs can one phone hold?
Apple says iPhone can manage up to eight or more eSIMs. With Dual SIM on iPhone, two numbers can be active at once for calls and messages, but only one cellular data network can be used at a time.
Can I use an eSIM for travel and keep my number?
Yes. Keep your home SIM in the phone for calls, texts and bank codes, and set the travel eSIM as the data line. Apple says a supported iPhone can have two eSIMs active at once while travelling.
Is an eSIM for travel data only?
A Slashtel eSIM is data only: there is no local phone number and no calls or SMS, though WhatsApp and other internet calls work over the data. Validity starts when the eSIM first connects at the destination.
Is an eSIM secure?
The GSMA runs SAS-UP accreditation for UICC/eUICC production sites and SAS-SM for subscription management sites, each with an on-site audit by GSMA-appointed auditors. TLS is mandated in the consumer remote provisioning protocol.