What is an eSIM?

How does eSIM technology work?

Understanding how eSIMs work helps demystify the technology and shows why they're so convenient for travelers. Here's the process broken down:

The activation process

1. Purchase a plan: You buy an eSIM data plan from a provider (like Airalo, Holafly, or your home carrier). This can be done entirely online from anywhere in the world.
2. Receive activation details: The provider sends you a QR code or activation code via email. This code contains the profile information needed to connect to their network.
3. Download the profile: You scan the QR code or enter the activation code in your device settings. Your phone downloads the eSIM profile over Wi-Fi or your existing data connection.
4. Install and activate: The profile is installed on your eSIM chip. You can name it (e.g., "Japan Travel"), choose when to activate it, and set it as your data line.
5. Connect to the network: When activated, your device uses the eSIM profile to connect to the mobile network, just like a physical SIM card would.

Behind the scenes

The eSIM chip contains secure storage and a special operating system that manages carrier profiles. When you download a profile, it's encrypted and securely stored on the chip. The chip can hold multiple profiles simultaneously (typically 5-10 on modern devices), though you can only use one or two at a time depending on your device's dual-SIM capabilities.

The technology follows the GSMA eSIM specification, an industry standard that ensures eSIM profiles work across different devices and carriers worldwide. This standardization is what allows you to buy an eSIM from a provider in one country and use it seamlessly in another.

A brief history of eSIM

While eSIM technology feels modern, its development spans over a decade. Understanding its evolution helps explain why it's finally becoming mainstream for consumers:

• 2010s - Industrial beginnings: eSIM technology (initially called M2M SIM) was first developed for machine-to-machine communication in industrial IoT devices, connected cars, and smart meters where physically changing SIM cards wasn't practical.
• 2016 - Consumer debut: The GSMA released the consumer eSIM specification. Samsung released the Gear S2 smartwatch with eSIM support, marking one of the first consumer applications.
• 2017 - Apple Watch Series 3: Apple brought eSIM to mainstream attention with cellular Apple Watches that could make calls independently of an iPhone.
• 2018 - iPhone XS/XR: Apple introduced eSIM to smartphones with the iPhone XS, XS Max, and XR, supporting dual SIM with one physical SIM and one eSIM. This was a major turning point for consumer adoption.
• 2019-2020 - Android adoption: Google Pixel 3 and Samsung Galaxy smartphones began supporting eSIM, followed by widespread adoption across flagship Android devices.
• 2022 - eSIM-only devices: Apple released the iPhone 14 series in the U.S. without a physical SIM card slot, making them eSIM-only devices. This represented the industry's confidence in the technology.
• 2024-2025 - Travel eSIM boom: The travel eSIM market exploded with dozens of providers offering prepaid data plans for 200+ countries, making international connectivity accessible and affordable.

Today, eSIM is standard in most premium smartphones, tablets, and smartwatches, with adoption expanding to mid-range devices as well.

Key features of eSIM technology

Several defining characteristics make eSIMs particularly valuable for modern mobile users:

1. Remote provisioning

eSIM profiles can be downloaded and activated remotely over the internet. This means you can purchase and activate a mobile plan from anywhere in the world without visiting a store or waiting for a physical SIM card to arrive by mail. For travelers, this means you can set up connectivity for your destination country before you even leave home.

2. Multiple profiles

Your eSIM chip can store multiple carrier profiles simultaneously. While you can typically only use one or two at a time (depending on your device's dual-SIM capabilities), you can keep several stored and switch between them in seconds through your device settings. This is perfect for frequent travelers who visit the same countries repeatedly—you can keep profiles for each destination installed and simply reactivate them when needed.

3. Dual SIM convenience

Most modern eSIM devices also have a physical SIM slot, enabling true dual SIM functionality. You can keep your home number on the physical SIM for calls and texts while using an eSIM for data when traveling. This way, you remain reachable on your regular number while enjoying affordable local data rates.

4. Instant activation

Once you download an eSIM profile, activation is nearly instantaneous. There's no waiting period, no need to restart your device, and no complicated setup. You scan a QR code, the profile downloads in seconds, and you're connected. This is especially valuable when you land in a new country and need connectivity immediately.

5. Enhanced security

Because the eSIM chip is embedded in your device, it can't be physically removed or stolen like a SIM card can. eSIM profiles are also encrypted and tied to your specific device, making them more secure than traditional SIM cards. If your phone is stolen, the thief can't simply remove the SIM and use it in another device.

6. Environmental benefits

eSIM technology eliminates the need for plastic SIM cards, packaging, and shipping. While each individual SIM card is small, billions are produced annually. The shift to eSIM represents a meaningful reduction in plastic waste and carbon emissions from logistics.

Why travelers love eSIM technology

For international travelers specifically, eSIM technology offers compelling advantages over traditional connectivity options:

Skip airport hassles

No more hunting for SIM card kiosks at the airport, dealing with language barriers, or waiting in long queues after a tiring flight. Buy your eSIM plan from your couch a few days before departure, install it at home, and activate it when you land. You'll have connectivity the moment you turn off airplane mode.

Avoid roaming bill shock

International roaming charges from your home carrier can be eye-wateringly expensive— often $10-15 per day just for basic data access. eSIM travel plans typically offer better value, with weekly plans often costing less than two days of carrier roaming. Because they're prepaid, you'll never face unexpected charges.

Stay reachable on your home number

With dual SIM functionality, you can keep your home SIM active for receiving calls and SMS (important for banking 2FA, verification codes, etc.) while using the eSIM for data. You don't have to choose between connectivity and accessibility.

Perfect for multi-country trips

If you're touring multiple countries, you can install regional eSIM plans (like a European plan that covers 30+ countries) or switch between country-specific plans on the fly. Some travelers keep multiple eSIM profiles installed and simply toggle between them as they cross borders—no need to find a new SIM card vendor in each country.

Backup connectivity option

Even if you have a good roaming plan or a local SIM, keeping an eSIM as a backup provides peace of mind. If your primary connection fails, you can quickly switch to your eSIM and remain connected. This is particularly valuable for business travelers or digital nomads who need reliable connectivity.

Try before committing

Many eSIM providers offer small, inexpensive plans (1-3 GB for $5-10) that let you test the service before buying a larger package. This is perfect for trying out coverage in a new destination or testing whether eSIM works well with your device.

Limitations to consider

While eSIM technology offers many advantages, it's important to understand its current limitations:

Device compatibility requirements

Not all phones support eSIM. Generally, you need a phone from 2018 or later, and it must be an eSIM-enabled model. Budget and mid-range phones often lack eSIM support, though this is changing. Always check your specific device model before purchasing an eSIM plan.

Carrier lock restrictions

Some carriers lock the eSIM functionality on phones they sell, even if the hardware supports it. You may need to unlock your phone with your carrier before you can use eSIM from other providers. This is particularly common with phones purchased on installment plans or contracts.

No device sharing

You can't remove an eSIM profile and put it in another device as easily as you can with a physical SIM card. While profiles can be transferred, the process is more complex and not all providers support it. If you frequently swap SIMs between devices, this may be inconvenient.

Internet required for activation

You need an internet connection (Wi-Fi or existing data) to download and install eSIM profiles. If you're in a location with no internet access and no existing data connection, you won't be able to set up a new eSIM until you find Wi-Fi.

Variable provider quality

The travel eSIM market has exploded, and not all providers offer the same quality of service. Coverage, data speeds, customer support, and reliability can vary significantly. It's important to research providers and read reviews before purchasing, especially for longer trips or business travel.

Data-only limitations

Most travel eSIM plans are data-only and don't include a local phone number. While you can make calls using apps like WhatsApp, FaceTime, or Google Voice over data, you won't have a local number for voice calls or SMS. Some providers offer voice add-ons, but they're less common and more expensive.

The future of eSIM technology

eSIM technology is still evolving, and several trends suggest where it's headed in the coming years:

Expanding device support

As manufacturing costs decrease and the technology matures, eSIM support is trickling down to mid-range and even budget devices. By 2026-2027, eSIM is likely to be standard across most new smartphones, making it accessible to billions more users worldwide.

eSIM-only devices

Following Apple's lead with the U.S. iPhone 14 models, more manufacturers are expected to release eSIM-only devices without physical SIM slots. This frees up internal space for larger batteries, better cameras, or improved water resistance. The transition will be gradual and market-dependent, but the trend is clear.

Integrated eSIM marketplaces

Future devices may include built-in eSIM marketplaces where you can browse, compare, and purchase plans directly from your phone settings without visiting individual provider websites. Apple and Google are both moving in this direction, making eSIM discovery and activation even simpler.

5G and beyond

As 5G networks expand globally, eSIM technology will enable seamless access to these high-speed networks. Future iterations may support even faster connectivity standards and more sophisticated network switching, automatically connecting you to the best available network in any location.

IoT expansion

Beyond phones and tablets, eSIM will power the next generation of connected devices— from laptops and cars to smart home devices and wearables. This ubiquitous connectivity will enable new use cases we're only beginning to imagine.

For travelers, the future looks bright. eSIM technology is making international connectivity simpler, more affordable, and more accessible than ever before. As the ecosystem matures, we can expect even more competition, better prices, and improved user experiences.