Are eSIMs reliable? Here’s how they really perform in 2026

Are eSIMs reliable? The short answer

So if you’re wondering whether eSIMs are reliable, the short answer is yes, they are, even when comparing an eSIM vs. a physical SIM card in terms of network reliability. Both are subscriber identity modules (SIMs), except an eSIM’s hardware is inside a phone and cannot be removed, hence the “e” prefix next to the SIM acronym, with the “e” standing for “embedded.”

eSIMs connect to the same cell towers and use the same networks as physical SIM cards. The fact that the card is embedded within a phone doesn’t change the fundamental way that cell towers identify your device or card or how the tower communicates with your device to provide you with connectivity and the ability to call or text your family, or use mobile data.

eSIMs’ reliability is affected by the same factors that would affect a physical SIM card’s reliability — your carrier’s network coverage, your location, and your device’s supported frequency bands.

The same applies to travel eSIM apps, like Saily. For example, if you’re traveling from the United States to Spain and buy the app’s data plan, you’ll get access to Saily’s local partners that provide network coverage throughout Spain just like you would access a network operator’s infrastructure with a local SIM card.

How eSIM reliability works

To understand why eSIMs’ reliability is affected by external factors rather than whether the module is a physical SIM card or embedded within the phone, we must explain how a device like a smartphone connects to a network.

SIM cards store the international mobile subscriber identity (IMSI) number and a key, known as the Ki, which helps the network identify the device, the subscriber, and what kind of network access they have to voice call minutes or SMS messages. The same working principle applies to an eSIM and continues applying even if you use dual SIMs like an eSIM and a physical SIM.

The difference is that you can physically remove a SIM card from your phone. An eSIM profile can be removed or turned off via the phone’s settings, but the module itself will remain installed on your phone’s motherboard. Having the ability to turn off or activate the eSIM on your phone is one of the main benefits of an eSIM — you won’t have to fiddle around with physical SIM cards every time you want to switch your operator. In addition, physical SIM cards can wear out, break, or since the nano SIM card became the standard, be lost due to their small size.

Are eSIMs as reliable as physical SIMs for coverage and speed?

Because eSIMs and physical SIMs work in almost exactly the same way — aside from where the module is located — their coverage and speed will be identical.

That does mean that the connectivity issues you face with a physical SIM can happen with an eSIM and vice versa. This usually happens in areas where local network operators don’t have extensive infrastructure, resulting in spotty connectivity. You will have coverage with an eSIM or a physical SIM in larger cities, but in deserts, mountainous regions, jungles, or remote areas, both an eSIM and a physical SIM can struggle with network connectivity.

The same is true for travel eSIMs. Since eSIMs connect to a local network’s infrastructure, their coverage and speed will be identical to a local SIM card. But unlike with physical SIM cards, an eSIM will save you from the process of buying a local SIM card, opening your SIM tray on your phone, swapping the two cards, and then storing your original SIM card somewhere safe.

In addition, with an eSIM, you’ll be able to use dual SIMs and stay connected to the internet via your travel eSIM and take any calls or SMS messages on your original SIM card.

Limitations: When eSIMs are less reliable

If you were to ask if there are any downsides to an eSIM, there are some. Whether eSIMs’ downsides weigh the scales in favor of physical SIM cards is up to you, but it’s hard to outweigh eSIMs’ convenience compared to regular SIMs.

First, while you don’t have to play around with SIM trays and physical SIM cards to install an eSIM or even multiple eSIM cards on your device, if you’re not particularly tech savvy, you might struggle with the process.

Usually, eSIM providers have clear instructions on how to install and use an eSIM card. With Saily, all you have to do is go to its website, purchase a plan for your destination or region, download the Saily eSIM app, and follow the instructions on the screen. If you’ve already used the Saily eSIM service, you can purchase a new plan, and it will activate automatically once you arrive at your destination. Other travel eSIM providers, as well as traditional mobile network operators, have similar processes to install an eSIM on your device.

Second, eSIMs suffer from the same problems that physical SIM cards do — lack of reliable coverage in remote areas with little network infrastructure. If that’s the case, there’s not much you can do. It’s worth checking coverage maps before you travel to your destination to ensure that you’ll be able to use a travel eSIM or even a local SIM card.

Third, eSIMs can suffer from software-related issues. Whether it’s an eSIM taking its time to activate or connectivity-related problems, such hiccups do sometimes happen. The good news is that troubleshooting an eSIM is easier than with a physical SIM card because you can redownload an eSIM profile, reactivate it, or try the classic method and restart your device.

If you can’t connect to a network with a physical SIM card, you might be facing issues that could be related to the SIM card itself or the SIM card reader inside your device. That could force you to visit your network operator’s physical store, or in the worst-case scenario, a repair shop that could take days to fix the SIM card reader. If you do encounter hardware issues with your eSIM, your problems could be deeper than just the inability to connect to a network, and you might be facing the cost of replacing the whole motherboard.

Fourth, not every device supports an eSIM. Most of the newer phones do, and in some regions, every new iPhone or Google Pixel device is eSIM only. If you’re carrying an older device, you might be out of luck. The fact that not every smartphone supports an eSIM isn’t exactly a reliability problem, but it can affect your ability to stay connected while traveling. Unfortunately, in this case, your only option is to buy a new smartphone.

Check the list of iPhone and Android devices that are compatible with a Saily eSIM.

Are eSIMs secure?

Beyond reliability, you might have questions about whether eSIMs are safe. After all, eSIMs are largely a software-based mobile network solution, and whatever is connected to the internet could be vulnerable to a cyberattack.

There’s some nuance to how vulnerable eSIMs are to being hacked. While eSIMs are considered safer than physical SIM cards since they cannot be copied or swapped into a perpetrator’s phone, eSIMs are still vulnerable to SIM swap fraud. The scam, also known as SIM jacking, involves criminals obtaining your personal information and using social engineering to convince your network operator to switch over your phone number to their SIM or eSIM. Once the transfer is complete, the wrongdoers can receive two-factor authentication (2FA) texts or any voice calls or SMS messages linked to you — gaining access to your bank accounts and other sensitive data.

However, eSIMs’ weak spot for SIM swapping shouldn’t discourage you from using an eSIM for your banking needs, for example. Much of the scam depends on social engineering and individuals’ carelessness on the internet, and if you browse smartly, you and your data will most likely be safe.

Some eSIM apps like Saily have integrated security features. The features include an ad blocker that turns off ads that appear while you browse, which can, at times, be malicious, web protection that blocks malicious sites and limits online trackers, and virtual location that lets you change — as the name suggests — the virtual location of your device.

Overall, eSIMs are safe — no more exposed to security risks than physical SIM cards.

What actually determines eSIM reliability

In short, three things determine whether your eSIM’s connection will be reliable:

• Your mobile network operator’s network coverage. Regardless if you have a travel eSIM, have switched over from a physical SIM to an eSIM, or are using dual SIM slots with one as an eSIM, your mobile network operator’s network infrastructure will determine how reliable your eSIM’s connection will be. Infrastructure-related considerations apply to travel eSIMs as well, and if you’re getting an eSIM for travel, research that provider’s partners or network offering in your destination.

• Your location. Even if a network carrier has a widely developed network, more remote areas will usually result in a lackluster or even non-existent connection. You can’t do much to prevent connectivity losses while on a mountain top or while you’re on an expedition in the jungle, apart from planning any important meetings or mapping out your itinerary beforehand.

• Your device’s supported frequency bands. Newer phones support faster network frequencies, including 5G. For example, the iPhone 17 has the capability to support 5G network download speeds, which can theoretically climb up to 20 Gbps in ideal conditions, compared to maximum download speeds of 4G of up to 100 Mbps. The iPhone 11 doesn’t support 5G, resulting in slower internet browsing speeds. In addition, 5G networks offer more capacity to network operators, which coupled with the faster download and upload speeds, ensure that your eSIM continues to reliably deliver you a network connection throughout the day.

A reliable eSIM you can count on: Saily

Picking out a reliable eSIM for your travels can seem like a daunting task. The current eSIM landscape has plenty of players vying for market share, but Saily is a standout eSIM app offering mobile data and phone number plans. With Saily, you will avoid potentially expensive international roaming charges, but you’ll also find reliable networks of partners in over 200 destinations.

In addition, Saily has the aforementioned security features that help you use an eSIM more safely and offers regional, the Global, or unlimited data plans, as well as the Saily Ultra plan. The subscription plan comes with data and travel perks like fast-track services at airports, airport lounge access, and complimentary lounge passes in case your flight gets delayed. Whichever plan you choose, you will have access to security features at no extra cost.