Travel eSIMs have become one of the easiest travel upgrades. You land, scan a QR code, switch on mobile data, and suddenly maps, WhatsApp, ride-hailing apps, hotel messages and boarding passes all work before you even leave the airport.

For Taiwanese travelers, that convenience is becoming harder to ignore as overseas travel rebounds. Many are choosing travel eSIMs instead of traditional roaming because they are cheaper, faster to activate and easier to compare. A few taps, a payment, a QR code, and the phone is ready for another country.

But a recent CNA-linked report has added a more serious question to the discussion: what happens when the cheapest eSIM is not transparent about where the data actually goes?

That is the part travelers often do not see. They compare prices, gigabytes and validity. They check whether the plan covers Japan, Korea, Europe or Southeast Asia. What they rarely check is the network path behind the product.

Why the warning matters

Chunghwa Telecom Chair Alex Chien warned that some travel eSIM operators may not properly apply “Know Your Customer” verification procedures. That makes it harder to identify the real origin of the service and the route used for data transmission.

This matters because mobile data is not just “internet.” It travels through networks, roaming partners, routing hubs and commercial agreements. If the provider is unclear, the user may not know whether their traffic is being routed through the destination country, another regional hub, or a network linked to a different jurisdiction.

Recent concerns have focused on reports that some low-cost travel eSIM services may route data through Chinese telecommunications networks. That does not mean every cheap eSIM is unsafe. It does mean travelers should stop assuming that all eSIMs are technically equal just because the QR code looks the same.

READ MORE: eSIM Security Is Becoming the Industry’s Real Differentiator

Technology commentator Hung Sheng-yi also warned that uncertain routing may increase the risk of interception in some regions. He raised another practical concern: eSIM profiles from unknown sources may include suspicious DNS settings, request unnecessary permissions, or expose users to data theft.

That last point is especially important for ordinary travelers. A normal travel eSIM should not need access to your photos, contacts, Bluetooth or sensitive location permissions just to give you mobile data. If an activation process feels strange, it probably deserves a pause.

Cheap is not always simple

The travel eSIM market has grown fast because it solves a real problem. Traditional roaming can be expensive, especially for people who travel often or visit several countries on one trip. A regional eSIM plan can be far cheaper than paying daily roaming fees to a home operator.

But the cheapest plan is not always the cleanest one.

Some budget eSIMs rely on international roaming resale arrangements. In practice, that can create odd behavior. A traveler may be physically in Tokyo, but a banking app may detect a login from another location. Messaging services may ask for verification. FaceTime or other communication tools may behave unexpectedly. A payment app may suddenly decide the session looks unusual.

READ MORE: Unveiling eSIM Security: Myths vs. Reality

This is where the hidden cost appears. Saving a few euros on data is nice. Losing access to banking codes, business apps or account verification while abroad is not.

Original-number roaming, although usually more expensive, still has a strong advantage here. Travelers keep their regular phone number active, which helps with one-time passwords, bank messages, airline alerts and account recovery. For business travelers, journalists, executives or anyone handling sensitive accounts, that continuity can be more valuable than the cheaper data price.

Chien also argued that roaming through a home operator can offer stronger reliability because telecom companies maintain direct agreements with local partners. That is a fair point. Serious travel eSIM providers can also offer excellent performance, but the weaker end of the market is often less transparent about routing, partners and support.

What travelers should check

The answer is not to avoid travel eSIMs. For many trips, they are still a smart and practical choice. The better answer is to buy them with more attention.

Start with the provider. Is the company clearly identified? Does it show customer support details? Does it explain which networks it uses? Is there a real refund policy? If the only selling point is a very low price, that is not enough.

Then check the plan details. Look beyond the headline price and compare cost per gigabyte, validity, hotspot support, fair usage rules and destination coverage. A cheap plan that slows down quickly or creates login problems may not be the best deal.

READ MORE: Cheap eSIMs, Long Data Routes, Real Privacy Questions

Travelers should also avoid unknown QR codes, suspicious reseller links and activation steps that request unrelated phone permissions. If an eSIM profile comes from a source you cannot verify, do not treat it as harmless.

For sensitive trips, it may be smarter to use original-number roaming, a trusted premium travel eSIM provider, or a mix of both. Many experienced travelers keep their home SIM active for banking and verification, then use an eSIM only for data. That is often the most practical setup.

Takeaway about Chunghwa Telecom eSIM warning

This warning from Chunghwa Telecom’s chair is not an argument against eSIMs. It is an argument against blind trust in the cheapest possible connectivity. Find out more about Chunghwa Telecom eSIM.

The market is splitting into two groups: transparent providers that compete on reliability, coverage, support and trust, and anonymous low-cost offers that compete mainly on price. Travelers should know the difference.

Roaming is no longer the only serious option. Travel eSIMs have changed how people connect abroad, and that is a good thing. But connectivity is still infrastructure. It has routes, partners, risks and accountability behind it.

The smartest travelers will not ask only, “How much data do I get?” They will also ask, “Who is providing it, where is it routed, and what happens if something goes wrong?”

Cheap data is useful. Trusted data is better.