An eSIM is a digital SIM card built directly into your device, allowing you to activate mobile plans without inserting a physical SIM card. This guide explains how eSIM technology works, the differences between eSIMs and traditional SIM cards, and why they have become popular for international travel. It also examines recent security research that found some travel eSIM providers route user traffic through unexpected third-party networks, discusses the privacy implications of those findings, and outlines practical ways to better protect your data while traveling. Whether you're choosing a travel eSIM, considering a local physical SIM, or looking for a more secure solution like a dedicated 5G mobile hotspot, this guide helps you understand the benefits, risks, and best practices for staying connected abroad.
If you've bought a new phone or planned an overseas trip recently, you've probably run into the term eSIM. An eSIM (embedded SIM) is a digital SIM card built directly into your phone's hardware. It does everything a physical SIM card does, just without the plastic chip. Instead of swapping cards, you download a carrier profile in minutes by scanning a QR code.
That convenience has made eSIMs the go-to choice for international travelers. But new research suggests that convenience can come at a cost: in May 2026, security findings reported in Taiwan revealed that many popular travel eSIMs quietly route user data through networks you'd never knowingly choose, based on a peer-reviewed study presented at the USENIX Security Symposium.
In this guide, we'll cover what an eSIM is, how eSIM technology works, what the latest research says about eSIM security risks, and what to do instead if you value your privacy.
What is an eSIM? An eSIM (short for embedded Subscriber Identity Module ) is a programmable SIM chip soldered directly onto your device's motherboard. Like a traditional SIM card, it identifies you to a mobile network so you can make calls, send texts, and use mobile data. The difference is that an eSIM is rewritable software: you can download, switch, and store multiple carrier profiles on a single device without ever opening a SIM tray.
Most flagship phones released since 2018 support eSIM, including iPhones, Samsung Galaxy, and Google Pixel devices, and some newer models in certain markets have dropped the physical SIM tray entirely.
eSIM vs. physical SIM: key differences
eSIM
Physical SIM
Form
Chip embedded in the device
Removable plastic card
Setup
Scan a QR code or use an app
Insert card manually
Switching carriers
Download a new profile in minutes
Buy and swap a new card
Multiple plans
Store several profiles at once
One plan per card
If your phone is stolen
Can't be removed by a thief
Can be pulled and discarded
How does an eSIM work? An eSIM works through a process called remote SIM provisioning . Here's the simplified version:
You purchase a plan from a carrier or travel eSIM provider, who issues a QR code or activation code.Your phone downloads the carrier profile , a small encrypted file containing your subscriber identity and network credentials, onto the embedded chip.The profile activates , and your phone connects to the carrier's network exactly as it would with a physical SIM.You can store multiple profiles and toggle between them in your settings. For example, you can keep your home number active while using a local data plan abroad.For travelers, the appeal is obvious: land in a new country, scan a code, and you're online before you reach baggage claim, often at a fraction of the cost of international roaming.
But here's the part most people never think about: when you install an eSIM profile, you're trusting an invisible chain of network operators with your data. And recent research shows that chain doesn't always go where you'd expect.
Are eSIMs a security risk? What the latest research found In May 2026, the Taipei Times reported on warnings raised by Taiwanese technology executive Nathan Chiu, who highlighted a study by Northeastern University researchers, "eSIMplicity or eSIMplification? Privacy and Security Risks in the eSIM Ecosystem," presented at the 34th USENIX Security Symposium. The research team purchased 25 travel eSIMs popular with international tourists and analyzed where each one actually sent its network traffic.
The findings were eye-opening:
Your traffic may be routed through countries you've never visited. Nearly all of the tested eSIMs showed IP addresses in locations that didn't match where the user actually was. In one example cited in the report, customers of a well-known Ireland-based eSIM brand were assigned IP addresses belonging to a Hong Kong-based subsidiary of China Mobile.
Hidden connections can be established without your knowledge. According to the findings, some eSIM profiles used the SIM application toolkit to silently open connections to overseas servers and receive text messages from foreign numbers, all invisible to the user.
Sensitive metadata travels with your traffic. The data routed through these third-party core networks reportedly included identifiers like your IMSI (subscriber identity), IMEI (device identity), location history, browsing behavior, and DNS queries.
Legal jurisdiction matters. The report noted that telecom operators registered in Hong Kong are subject to China's Cybersecurity Law and National Intelligence Law, which compel cooperation with state intelligence agencies. In other words, the question isn't just whether your eSIM provider protects your data. It's which country's laws govern the networks your data passes through.
There's a practical side effect, too: if your traffic exits through an IP address in China, Hong Kong, or Macau, services like ChatGPT, Claude, or Gemini may simply refuse to work, even though you're physically sitting in Tokyo or Paris. Many travelers blame their hotel Wi-Fi and never realize their eSIM is the culprit.
To be clear: the eSIM standard itself is not broken. The embedded chip and its encryption are sound technology. The risk lies in the business layer : which networks a budget eSIM reseller leases capacity from, and where your packets travel before reaching the open internet.
If you value your privacy, do this instead
You don't have to give up the convenience of staying connected abroad. You just need to be deliberate about how . Here are four steps, from baseline protection to the most secure setup.
1. Always use a VPN A VPN (virtual private network) encrypts your traffic before it leaves your device, so even if your data is routed through an untrusted core network, the operators along the way see only encrypted packets rather than your browsing activity, DNS queries, or destinations. A VPN won't hide all metadata (your device still registers on the cellular network), but it dramatically shrinks what intermediaries can see. Treat it as non-negotiable on any travel connection, eSIM or otherwise.
If you're not sure which VPN to use, check out our article on the best no-log VPNs in 2026 .
2. Buy eSIMs only from reputable providers The Northeastern study tested budget travel eSIMs, exactly the kind sold through ads promising "5GB for $3." Cheap resellers often lease capacity from whichever wholesale network is cheapest, with little transparency about routing. Choose established providers that publish clear privacy policies and have a reputation to protect. Saily , for example, is run by the team behind NordVPN and bundles VPN-grade protection with its travel eSIMs, a sensible pairing given everything above. Whoever you choose, a provider's privacy practices should weigh at least as heavily as its price per gigabyte.
3. Consider a physical SIM from a local carrier It sounds old-school, but buying a prepaid physical SIM from a licensed local telecom at your destination keeps your traffic on that country's regulated domestic network, with no opaque international resale chain in between. Major national carriers sign direct interconnection agreements and operate under local telecom law and oversight. The trade-offs are real (airport queues, ID registration requirements, fiddling with a SIM ejector tool), but for privacy-conscious travelers, knowing exactly whose network you're on is worth the friction.
4. Use a mobile hotspot as a security buffer between the network and your phone The most robust option is to take your phone off the cellular network entirely and put dedicated hardware in between. A 5G mobile hotspot like the Acer Connect M6E 5G Mobile WiFi acts as an intermediary between the carrier and your personal devices:
Your phone's identity never touches the foreign network. The SIM or virtual SIM lives in the router, so it's the router's identifiers that register with the local carrier, not your phone's IMEI or your personal number.One protected connection for every device. The M6E connects to 5G networks in 135+ countries and shares the connection over a WiFi 6E hotspot secured with WPA3 encryption, a built-in firewall, SIM lock, and VPN support, so your phone, laptop, and tablet all sit behind the same protective layer.Always patched. Automatic software and firmware updates keep the device hardened against new threats without you having to think about it.Built for the road. With up to 28 hours of battery life, IP68 water and dust resistance, and military-grade durability, it's designed for exactly the kind of travel where connection security matters most.Pair the M6E with a VPN running at the router level, and every device you carry gets encrypted, identity-shielded connectivity from a single piece of hardware.
The bottom line on eSIM security eSIMs are a genuinely useful technology: convenient, flexible, and here to stay. But the 2026 research is a reminder that "connected in seconds" can also mean "routed through networks you never agreed to." Before your next trip: install a VPN, choose providers with transparent privacy practices, and for the strongest protection, put dedicated hardware like the Acer Connect M6E between your devices and the network.
Your data will travel with you either way. Make sure you decide who gets to see it.
Frequently asked questions What is an eSIM in simple terms?
An eSIM is a digital SIM card built into your phone. Instead of inserting a plastic card, you download your mobile plan by scanning a QR code. It does everything a regular SIM does (calls, texts, and data) without the physical chip.
How does an eSIM work when traveling?
You buy a data plan online from a carrier or travel eSIM provider, scan the QR code they send you, and your phone downloads the carrier profile. You're connected to a local network on arrival, without visiting a store or swapping SIM cards.
Are eSIMs safe to use?
The eSIM standard itself is secure: profiles are encrypted and can't be physically stolen like a SIM card. The risk lies with some providers. 2026 research found that many budget travel eSIMs route user traffic and metadata through third-party networks in other countries without the user's knowledge.
Is an eSIM more secure than a physical SIM?
In some ways, yes. An eSIM can't be removed by a thief and is harder to clone or swap. But a physical SIM from a licensed local carrier keeps your traffic on a regulated domestic network, which can offer better privacy than a cheap travel eSIM with opaque routing.
How can I protect my privacy when using an eSIM?
Use a VPN at all times, buy only from reputable eSIM providers with clear privacy policies, or route your connection through a secure mobile hotspot like the Acer Connect M6E so your phone's identifiers never register on the foreign network.
Why can't I access ChatGPT or other apps with my travel eSIM?
Some travel eSIMs route traffic through IP addresses in China, Hong Kong, or Macau, where certain US-based AI services are unavailable. The services see your exit IP location rather than where you physically are, and block the connection.
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