How does an eSIM work: guide for beginners
An eSIM is a chip soldered onto the smartphone’s motherboard that replaces the plastic SIM. Instead of inserting a physical card, you download an operator profile via the internet in the form of a QR code. Here is the operational guide: what it is, how to activate it, which devices support it, and what to expect on first use.
An eSIM is an embedded chip that replaces the physical SIM. It is activated by downloading an operator profile via QR code or app, in 5 minutes, without going to a store. Plan validity starts from activation, not installation: you can install it before departure and activate it on arrival. It requires a compatible smartphone (iPhone XS+, Pixel 3+, Galaxy S20+). It can be used together with the main physical SIM.
What is an eSIM, in simple terms
eSIM stands for “embedded SIM”: it is a chip soldered onto the smartphone’s motherboard, a few millimeters in size. It performs the same function as the classic plastic SIM: it identifies your number with the operator and manages voice, SMS, and data traffic. The difference is that it is not removable and is programmed via software.
It is a chip, not a card
The eSIM is not inserted into a slot: it is soldered onto the motherboard. It cannot be physically removed and is not lost if the phone falls.
The operator profile is software
Instead of the physical SIM with the operator’s data, the eSIM receives a profile via the internet in the form of a QR code. The profile is programmable and replaceable.
You can have multiple profiles
A smartphone supports 5 to 10 eSIM profiles, with 1-2 active in parallel. You can have one profile for Europe, one for Asia, one for the USA, and activate only the one you need.
The substantial difference is not the absence of plastic, but programmability. With a physical SIM, the profile is fixed on the card: to change operator, you must change SIM. With an eSIM, the profile is software: you can install multiple profiles, activate them at different times, and change operator in 5 minutes without physical movements.
eSIM vs physical SIM: key differences
An operational summary. Values must be verified because they vary by operator and country.
| Dimension | eSIM | Physical SIM |
|---|---|---|
| Format | Chip soldered onto the motherboard | Removable plastic card |
| Activation | Online via QR code / app, 5 minutes | Physical, in store or with shipping |
| Operator change | Immediate from the app | Requires a new SIM |
| Main SIM in parallel | Yes, natively supported | Only with physical dual SIM |
| Device support | Recent smartphones only | Universal |
| Local number | Rarely included | Often included |
| Theft resistance | High (non-removable) | Low (removable) |
| Device transfer | Operator procedure | Physical, immediate |
How an eSIM works: the technical flow in simple terms
How an eSIM works is simpler than it seems. The operator profile is downloaded via the internet and programmed directly onto the chip. From that moment, the eSIM behaves exactly like a physical SIM: it connects to the local operator’s network and manages voice, SMS, and data according to the activated plan.
What happens when you buy an eSIM plan
Step 1: You purchase the plan on the provider’s website or app (e.g., Airalo, Holafly, Nomad). You receive a QR code via email that contains the operator profile.
Step 2: From your smartphone, open the eSIM settings (iOS: Settings → Cellular → Add eSIM; Android: Settings → Network → SIM → Add eSIM). Scan the QR code.
Step 3: The profile is downloaded and programmed onto the eSIM chip. The phone asks you to label it (e.g., “Japan Trip”) and to choose whether to use it for data, voice, or SMS.
Step 4: On arrival in the destination country, activate the eSIM from the settings. Plan validity starts from activation, not installation.
Step 5: The phone connects to the local supporting operator’s network and starts working like a traditional SIM.
What an eSIM is NOT
- It is not an app. It is a physical chip soldered onto the motherboard, not software you install.
- It is not an operator. It is a technical format. eSIM operators are MVNOs (Airalo, Holafly, Nomad) that resell network capacity from local operators.
- It is not “data only” by definition. It can manage voice, SMS, and data. It depends on the plan the operator sells.
- It is not incompatible with the physical SIM. You can use both in parallel if the device supports it.
The point is not “eliminating plastic”, but being able to change operator profile without changing the card. This enables scenarios that are inconvenient with a physical SIM: two active lines in parallel, different profiles for different countries, operator change in 5 minutes. Dematerialization is a side effect, not the goal.
Which smartphones support eSIM
eSIM is not supported by all smartphones. Before purchasing a plan, verify your device’s compatibility.
| Manufacturer | Compatible models (main) | Notes |
|---|---|---|
| Apple | iPhone XS, XS Max, XR and all later models (2018+) | Full support, quick activation |
| Pixel 3 and later (2018+) | Full support on all versions | |
| Samsung | Galaxy S20 and later, Note 20, Z Flip, Z Fold | Full support on flagship models |
| Huawei | P40, P40 Pro, Mate 40 Pro | Partial support, verify specific model |
| Xiaomi | Xiaomi 12T Pro, 13, 14 and later | Support on recent flagship models |
| Oppo | Find X3 Pro and later | Verify specific model |
| Motorola | Razr 2019 and later | Support on recent foldables |
Quick method: open your phone’s keypad and dial *#06#. If a number called EID (Embedded Identity Document) appears, your smartphone supports eSIM. If nothing appears, the device is not compatible.
Official method: consult the manufacturer’s official list (Apple, Google, Samsung) or your model’s technical sheet.
On older smartphones (pre-2018) or recent budget models, eSIM may not be supported. In that case, the physical SIM remains the only option. Verify before purchasing any eSIM plan: a non-refundable plan purchased by mistake on an incompatible device is a waste.
How to activate an eSIM: step-by-step procedure
The procedure is simple and takes about 5 minutes. Here is the complete operational flow.
Purchase the plan on the provider’s website or app (Airalo, Holafly, Nomad, aloSIM). Choose destination, duration, and data volume. Complete payment with credit card or PayPal. The QR code is sent by email within minutes.
Open the smartphone’s eSIM settings. iOS: Settings → Cellular → Add eSIM. Android: Settings → Network and Internet → SIM → Add eSIM. Scan the QR code received by email. The profile is downloaded and programmed onto the chip.
The phone asks you to label the profile (e.g., “Japan Trip”) and to choose the default use. Set the eSIM as the data line and leave the main SIM for voice and SMS. Disable data roaming on the main SIM to avoid unwanted costs.
On arrival in the destination country, activate the eSIM from the settings (iOS: Settings → Cellular → [eSIM name] → Turn On Line; Android: similar procedure). The phone connects to the local operator’s network and the connection becomes active within seconds.
Verify that the connection works: open the browser, send a WhatsApp message, test the hotspot. If something does not work, check that data roaming is active on the eSIM (it is the standard setting for travel eSIMs) and that the mobile network is correctly selected.
Monitor data consumption from the phone’s settings. Most providers send a notification when the plan is close to running out. If you expect to exhaust the GB before the end of the trip, consider an add-on (Nomad) or a top-up (Airalo).
Plan validity starts from activation, not installation. Installing the profile before departure (at home, with stable Wi-Fi) eliminates the risk of technical problems on arrival. Activating the eSIM only on arrival avoids consuming plan days during the trip. This sequence is the correct way to manage any travel eSIM.
How much an eSIM costs: pricing structure
The cost of an eSIM depends on three factors: destination, duration, and data volume. The list price is only part of the real cost: you must also consider the operational time saved compared to the physical SIM.
| Plan type | Destination | Indicative price | Ideal for |
|---|---|---|---|
| Small fixed plan | Europe, USA | ~$4.50 for 1 GB / 7 days | Weekend, light use |
| Medium fixed plan | Europe, USA | ~$16-26 for 5-10 GB | 1-2 weeks, tourism |
| Large fixed plan | Europe, USA | ~$30-40 for 20-30 GB | 2-4 weeks, work |
| Regional plan | Europe, Asia, North America | ~$20-37 for 5-10 GB | Multi-country 1-4 weeks |
| Unlimited plan | Europe, USA, Asia | ~$27.30 / 7 days, ~$74.90 / 30 days | Intensive work, hotspot |
| Long global plan | 82-137 countries | ~$20-80 (Nomad Global-EX 365 days) | Digital nomads, long trips |
The price of a local SIM may seem lower, but the real cost includes: travel to the store (30-60 minutes), document presentation, activation times, possible mandatory registration. On a short trip, the value of the time invested exceeds the savings on the price. The eSIM eliminates this cost. The real cost of a physical SIM is not just the plan price.
A 1 GB fixed plan at $4.50 seems cheap, but runs out in 2 days with normal use. A 10 GB plan at $26 has a lower per-GB price ($2.60/GB versus $4.50/GB). If you expect to consume more than 1 GB during the trip, the larger plan is more efficient. Always compare the cost per GB, not the absolute price.
When eSIM is the right choice
This is not a ranking. It is a matrix to orient yourself based on your type of trip.
| Scenario | Is eSIM the right choice? | Why |
|---|---|---|
| Weekend in a European capital | Yes | Quick activation, cheap small plans |
| 2 weeks multi-country (Europe) | Yes | Regional plan, a single profile for multiple countries |
| 1 month of remote work in Asia | Yes (unlimited) | Holafly or Nomad for worry-free hotspot |
| 6 months in a single country | It depends | Local SIM can be cheaper on per-GB price |
| Trip with active banking 2FA | Yes | Main SIM stays active in parallel |
| Older smartphone (pre-2018) | No | Device does not support eSIM |
| Countries with mandatory SIM registration | Yes | eSIM avoids bureaucratic procedures that take days |
The main exceptions are: older smartphones that do not support eSIM, stays of 6+ months in a single country where a local SIM is cheaper on per-GB price, and specific cases where a local number is needed (contracts, local banking services). In all other scenarios, the eSIM wins on convenience and real cost.
The 5 most common mistakes with eSIM
These mistakes are not disastrous individually. They become relevant when repeated and compromise connectivity during the trip.
Plan validity starts from activation. If you activate the eSIM a week before departure, you lose a week of plan. Install the profile at home (with stable Wi-Fi) but activate the line only on arrival in the destination country.
eSIM is supported by iPhone XS+, Pixel 3+, Galaxy S20+. Some recent budget models do not support it. Verify compatibility by dialing *#06# before purchase: if an EID appears, the device is compatible.
The main SIM must remain active to receive calls and SMS on your usual number, including banking 2FA. The eSIM is used only for data. Deactivating the main SIM compromises access to critical services.
Travel eSIMs work with data roaming active (it is their standard operation). If roaming is disabled on the eSIM, the connection does not work on arrival. Enable data roaming on the eSIM, disable it on the main SIM to avoid unwanted costs.
After activation, do an immediate test: open the browser, send a WhatsApp message, test the hotspot. If something does not work, you have time to fix it before you need it. The worst moment to discover a connection problem is during a work video call.
The eSIM has different logics: it is installed and activated at separate times, requires active roaming, and can coexist with the physical SIM. Those who apply physical SIM habits (insert and use immediately) tend to make mistakes that compromise connectivity. Read the provider’s procedure before first use.
Roadmap for your first eSIM setup
A practical sequence to configure your first eSIM without errors.
Dial *#06# on your phone’s keypad. If an EID appears (a long 32-digit number), the device supports eSIM. If it does not appear, eSIM is not supported.
For short trips: Airalo or aloSIM with fixed plans. For work with hotspot: Holafly unlimited. For long trips: Nomad with large bundles or Global-EX. Verify the specific country’s coverage before purchase.
Online purchase, payment with card or PayPal, receipt of the QR code via email. Do not scan the QR code before reading the provider’s procedure.
Open the smartphone’s eSIM settings and scan the QR code. The profile is installed but not activated. Label the eSIM (e.g., “Japan Trip”). Set the main SIM for voice and SMS, the eSIM for data.
On arrival in the country, activate the eSIM from the settings. Verify that data roaming is active on the eSIM and disabled on the main SIM. The phone connects to the local network within seconds.
Do a functionality test (browser, WhatsApp, hotspot). Monitor data consumption from the settings. If the plan runs out before the end of the trip, consider an add-on or a top-up. For more on providers, read The best international eSIMs.
The first eSIM purchase takes time to understand the flow: verify compatibility, choose provider, install profile, configure lines. From the second purchase onward, the flow becomes automatic: choose the plan, receive the QR code, install and activate. If you plan frequent trips, the learning curve amortizes over 2-3 uses.
Continue your journey on SmartStackHubPro
The eSIM is one piece of the connectivity architecture for travelers. These contents complete the picture.
Official sources and references
The data on activation, compatibility, and features cited in this article are based on official sources. Always verify updated conditions before making decisions.
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Frequently asked questions about how an eSIM works
The answers summarize the article’s framework. Conditions vary by operator and country.
What is an eSIM in simple terms?
An eSIM (embedded SIM) is a chip soldered onto the smartphone’s motherboard that replaces the classic plastic SIM. Instead of inserting a physical card, you download an operator profile via the internet in the form of a QR code. Once installed, the profile works exactly like a traditional SIM: it receives and sends data, calls, and SMS according to the activated plan.
How do you activate an eSIM step by step?
The standard flow is in 5 steps: 1) purchase the plan on the provider’s website or app, 2) receive the QR code via email, 3) open the smartphone’s eSIM settings, 4) scan the QR code, 5) activate on first connection to the local network of the destination country. The profile can be installed before departure and activated on arrival.
Does my smartphone support eSIM?
eSIM is supported by iPhone XS and later (2018 onwards), Google Pixel 3 and later, Samsung Galaxy S20 and later, and many recent models from Huawei, Xiaomi, Oppo, and other manufacturers. To verify, dial *#06# on your phone’s keypad: if an EID (Embedded Identity Document) appears, your device supports eSIM.
Can I use my physical SIM and eSIM at the same time?
Yes, smartphones with eSIM support allow you to keep both the main physical SIM and the eSIM active in parallel. You can receive calls and SMS on your main number while using the eSIM for local data. In the phone’s settings you can choose which line to use for data, voice, and SMS.
How much does activating an eSIM cost?
Activation itself is free: you only pay for the data plan you purchase. Travel eSIM plans start at around $4.50 for 1 GB / 7 days (Airalo, aloSIM), with Europe regional plans around $20-37 for 10 GB. Holafly unlimited plans start at around $3.90/day. The QR code is sent by email at the time of purchase and has no additional cost.
What happens if I change smartphones? Can I transfer the eSIM?
Transferring the eSIM to a new smartphone depends on the provider. Some providers allow you to generate a new QR code from the app or account and reinstall the profile on the new device. Others require contacting support. In general, the eSIM is not transferable like a physical SIM: you need a new QR code.
Does eSIM consume more battery than physical SIM?
No, under normal conditions the battery consumption difference between eSIM and physical SIM is negligible. Both use the same radio modem of the smartphone. If you keep two lines active simultaneously (physical SIM + eSIM), consumption may increase slightly because the phone manages two connections.
Can I install multiple eSIMs at the same time?
Yes, modern smartphones allow installing multiple eSIM profiles at the same time (typically 5 to 10 profiles, depending on the model). However, only one or two eSIMs can be active at a given time, depending on the device. This allows you to have different profiles for different countries and activate only the one you need.
General Information: The information contained in this article, including references to eSIM services, comparative evaluations, coverage data, and prices, is published exclusively for informational and educational purposes. SmartStackHubPro.com does not provide legal, technical, or connectivity advice. The characteristics of eSIM services (prices, available countries, hotspot policies, features) change over time and must always be verified on the providers’ official documentation.
Affiliate Transparency: Airalo, Holafly, Nomad eSIM, and aloSIM are affiliate links. If you decide to purchase through these links, SmartStackHubPro may receive a commission at no additional cost to you. The selection and placement of services in this comparison are determined by editorial criteria and are not influenced by commercial agreements.
An eSIM is a programmable chip activated via software: understanding it is the key to using it well.
Once you understand how it works, the eSIM is simpler than a physical SIM: no stores, no waiting, no searching for points of sale. You buy online, install the profile at home, activate it on arrival, and the phone is connected within seconds.
The key points for a beginner: verify your device’s compatibility (dial *#06#), install the profile before departure, activate it on arrival, keep the main SIM active for 2FA and work, enable data roaming on the eSIM.
With these 5 rules, the first use of the eSIM becomes a 15-minute operation without risks. From the second onward, 5 minutes.
