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What is eSIM and How Does It Differ from a SIM Card
Команда OneVOIPlanet · Updated 2026-07-22
What is eSIM: A Simple Explanation of the Technology
The acronym stands for embedded SIM—a built-in SIM card. It is a microchip measuring approximately 6x5 millimeters that is soldered to the device's motherboard at the factory. Physically inserting anything into the phone is no longer necessary. The technology is not brand new. It was initially developed for the M2M (Machine-to-Machine) segment—smart meters, industrial sensors, payment terminals, and automotive electronics. In such devices, physical access to the card tray was difficult or required extra maintenance costs. When manufacturers realized the convenience and reliability of this solution, the technology was adapted for consumer electronics. Since 2017, eSIM has begun appearing en masse in smartwatches and, later, in flagship smartphones.
How Does a Virtual SIM Card Work?
eSIM technology relies on a rewritable chip embedded in the device's motherboard. Instead of a plastic card with fixed carrier data, a digital profile is downloaded to the device over the internet using Over-The-Air (OTA) technology. Connection occurs via remote authentication: the user scans a QR code provided by the operator or enters a code manually. The device then contacts the operator's server, receives encrypted access keys to the network, and stores them in a secure segment of the chip. A single eSIM chip can store multiple profiles simultaneously—from different carriers and with different plans. In most modern smartphones, this ranges from 5 to 10 profiles depending on the model. Switching between them is done in the operating system settings and takes just a few seconds.
Key Differences Between eSIM and a Physical SIM Card
The primary difference is the change in physical format. There is no tray, no SIM ejector tool needed to open it, and the smartphone body loses an extra moving part. All connection data associated with the phone number now resides in a digital profile written directly onto the device's chip. This directly impacts security. A plastic SIM card can be physically removed and thrown away to disconnect from the internet and make tracking a stolen phone difficult. With an eSIM, this is impossible: the chip is soldered into the board, and the system will not allow deleting a profile without the unlock password. This gives the owner time to track the device's location using tracking services. The difference is also noticeable in service management. To change carriers or activate a new number, you don't need to visit a mobile shop, wait in line with documents, or wait for a courier delivering a physical SIM card. The agreement is made and verified via an app, and the new plan is downloaded in 10-15 minutes.
Advantages of Using eSIM
Eliminating the physical slot, contact points, and tray ejection mechanism frees up internal space inside the smartphone. Manufacturers use this space for a larger capacity battery, a more sophisticated cooling system, or a larger camera sensor. The absence of a SIM tray opening also simplifies sealing—fewer seams mean fewer chances for moisture or dust to get inside, directly improving protection ratings such as IP68. There is also an economy-of-scale effect. Billions of plastic SIM cards are manufactured worldwide every year: oil is extracted for plastic, paper packaging is printed, freight is shipped via trucks and planes, and within a few years, these cards end up in landfills where the plastic is rarely recycled. eSIM removes this entire supply chain: the profile is delivered as data, without manufacturing, packaging, or transporting a physical carrier. For the operator, this means direct savings on distribution, and for the user, a reduced contribution to plastic waste.
Drawbacks and Limitations of the Technology
The biggest issue arises during sudden hardware failure of the smartphone. If a device breaks, falls into water, and fails to turn on, you cannot simply swap the card into a spare feature phone in seconds to take an important call. You will need to find another eSIM-compatible smartphone and go through the profile restoration process via carrier customer support. Other drawbacks are related to market adoption. Embedded microchips are currently installed mostly in flagship devices and upper-mid-range smartphones. This feature is virtually nonexistent in budget models under $200. Issues with eSIM also regularly arise when traveling to developing countries. Not all local operators in Africa, parts of Asia, or South America have upgraded their equipment to support OTA profile downloads, so tourists are still sold strictly traditional plastic cards.
Which Devices Support eSIM?
The technology is supported primarily by flagship lines of leading brands. Apple began introducing eSIM in 2018 with the iPhone XS, XS Max, and XR models. Today, the feature is available on all models from iPhone 11 onwards. On Android, Google was first with its Pixel line starting from Pixel 2. Samsung integrates eSIM into the Galaxy S series from S20 onwards, as well as into its Z Fold and Z Flip foldable smartphones. Smartphones are not the only devices. Smartwatches physically lack space for a SIM card slot, making eSIM not just an alternative, but the only option for cellular connectivity. Apple Watch Cellular versions, Samsung Galaxy Watch, and Google Pixel Watch allow users to receive calls and stream music online without a phone nearby. Microchips are also installed in top-tier tablets—Apple iPad Pro and Microsoft Surface Pro gain independent internet access thanks to this technology.
How to Connect and Set Up eSIM: A Step-by-Step Guide
To connect an eSIM, first download the official app of your mobile operator or visit their website. Choose a plan, complete identity verification—usually via banking systems or government portal services—and the operator will generate a unique QR code. Next, the setup varies slightly depending on the operating system. On iOS: Go to Settings → Cellular → Add eSIM, then scan the QR code with your camera. If the code arrived as a digital file rather than printed, you can upload it as an image from your gallery to scan it. On Android: Go to Settings → Connections → SIM Manager → Add Mobile Plan. After scanning the code, the system will ask for confirmation. Within 1–2 minutes, the device will connect to the operator's server, download the encrypted profile, and register on the network.
Lifehack: Using eSIM for Affordable Travel Internet
International roaming from your home operator is usually significantly more expensive than a local plan in your destination country. Abroad, it is more cost-effective to connect a separate digital profile—a so-called travel eSIM. There are specialized providers selling data packages for specific countries and regions, such as Airalo, Holafly, Nomad, and others. The process is simple: while still at home, select a package—for example, 10 GB for European countries valid for 14 days—and install the profile on your phone. After landing, simply turn off airplane mode: the smartphone connects to the local network using the selected package rates, with no extra steps required. A travel profile works in parallel with your main SIM card. In your phone settings, the physical SIM remains active solely for calls and SMS—for instance, to receive bank verification codes—while all mobile data traffic goes through the international eSIM profile.
The Evolution of Technology: From eSIM to iSIM
Physical SIM cards are gradually disappearing from mobile devices. Starting with the iPhone 14 lineup, Apple smartphones made for the US market are manufactured completely without a SIM tray. The next step in this evolution is iSIM (Integrated SIM) technology. Unlike eSIM, which remains a separate chip soldered to the motherboard, iSIM integrates the cellular module directly into the processor architecture (SoC). Qualcomm is already incorporating this technology into its flagship Snapdragon chipsets. By moving into the SoC, the connectivity module becomes more compact, consumes less energy, and is cheaper to mass-produce. This paves the way for cellular connectivity in devices where there is simply no space for a separate chip: augmented reality glasses, compact medical trackers, and more.
Frequently Asked Questions (FAQ)
Can I use an eSIM and a physical SIM card at the same time? Yes—most modern smartphones support Dual SIM mode: one number works on a plastic card, another on the built-in chip, and both can receive calls and data. How many eSIM profiles can a phone hold? The chip memory typically stores 5 to 10 profiles depending on the model. Only one or two can be active simultaneously, depending on the number of cellular modems in the processor. This does not affect battery life: a digital profile does not consume energy maintaining physical contact like a plastic card. How do I delete an eSIM before selling a phone? In cellular settings, find the mobile plan and tap "Delete Plan" or "Erase eSIM". A factory reset should only be performed after the profile has been completely erased from the chip memory.