eSIM & SIM Cards

The Options

You have roughly three paths to mobile data when traveling:

1. Physical SIM card from a local provider at your destination
2. eSIM from a digital provider (local or regional coverage)
3. Roaming on your existing home plan

None of them is universally "the best." Which one makes sense depends on where you are going, how long you are staying, whether your phone supports eSIM, whether you need calls and SMS, and how much you care about having data the second you step off the plane.

That is a lot of variables. So let me walk through each one.

Physical SIM from a Local Provider

The old school approach. You land, find a mobile shop (ideally not the one inside the airport that charges triple), hand over your passport, and walk out with a local SIM card. Done.

What is good about it:

• Usually the cheapest option per gigabyte, sometimes absurdly cheap
• You get a local phone number, which can matter (WhatsApp registration, local services, calling your AirBnb because no one's home, getting onto a viewing platform in China etc.)
• Works on every phone, no eSIM support needed
• Staff at the shop will usually set it up for you, which is nice if APN settings give you anxiety

What is not so good:

• You have no data from landing until you get to the shop. If you are the type who needs Google Maps to find the exit, that is a problem
• Airport SIM shops are overpriced (yet oftentimes still cheaper than eSIM providers). City shops are cheaper but you need to get there first
• Some countries require passport registration, which can take time or get bureaucratic
• You need to physically swap your SIM, which means either losing your home number temporarily or carrying a dual-SIM phone
• If you are hopping between countries, you need a new SIM for each one

Real world example: In Laos, airport SIM cards are surprisingly cheap. Like, suspiciously cheap. Meanwhile, eSIM providers charge a small fortune for Laos coverage. That is one of those countries where the physical SIM wins by a landslide.

When it makes sense:

Longer stays in one country. Budget trips where every dollar counts. Destinations where local SIMs are dirt cheap and easy to get (most of Southeast Asia, for example). Or when you need a local number for practical reasons.

eSIM from a Digital Provider

This is the newer approach and it is genuinely convenient. You buy an eSIM online before your trip, scan a QR code, and your phone connects to a local or regional network when you arrive. No shop, no passport, no SIM swapping.

But not all eSIMs are created equal. There are two flavors:

Local eSIMs connect you to one specific carrier in one specific country. You buy a Thailand eSIM, you get data on a Thai network. Simple. Better speeds and reliability because you are on a proper local network. Often cheaper than regional eSIMs for the same amount of data. Sometimes includes a local phone number, but not always, so check before you buy.

Regional eSIMs cover multiple countries. "Southeast Asia," "Europe," "Global," that kind of thing. One eSIM, many borders. Super convenient for multi-country trips because you do not need a new eSIM every time you cross a border. But they are more expensive per gigabyte, speeds can be inconsistent because you are roaming on partner networks rather than being a direct customer, and they rarely include a phone number.

The general eSIM situation:

• Your phone needs to support eSIM. Most phones from the last few years do, but check yours
• You keep your home SIM active in the other slot, so you still receive SMS and calls on your regular number (handy for two-factor authentication)
• Setup takes five minutes from your couch the night before departure
• Data works the moment you land and turn off airplane mode
• No human interaction required, which is either a pro or a con depending on how you feel about people

Providers worth looking at: Roamless, Nomad, aloSIM, and others. Prices and coverage vary wildly. And I mean wildly. One provider might charge you three times what another one charges for the same country with the same amount of data, sometimes on an even worse network. In another country, the roles are completely reversed. There is no single "best" provider. Always compare prices for your specific destination before you buy.

On longer multi-country trips, I regularly end up with eSIMs from three different providers and a physical SIM card or two rattling around in my pocket by the end. It looks chaotic. It is chaotic. But it is also the cheapest way to do it.

When in China: In China, an eSIM is not just convenient, it is arguably the best option. Most eSIM providers route your traffic in a way that effectively bypasses the Great Firewall. That means Google, WhatsApp, Instagram, and everything else just works without fiddling with VPNs. A local Chinese SIM will not do that for you. Important: You must set it up before you land in China.

When it makes sense:

Short to medium trips. Multi-country itineraries (regional eSIM). When you want data immediately on arrival. When your phone supports eSIM and you do not need a local phone number.

Roaming

Just use your existing plan abroad. Turn on roaming, done. The simplest option by far.

What is good about it:

• Zero effort. Your phone just works
• You keep your number, your calls, your SMS, everything
• Some plans include generous roaming. EU residents roam for free within the EU. Some premium plans worldwide include roaming data
• No setup, no SIM swapping, no QR codes

What is not so good:

• If your plan does not include roaming or has limited roaming data, costs can get ugly fast
• Even included roaming often has fair-use caps or speed throttling
• Outside the EU or your carrier's roaming zone, per-megabyte charges from the early 2000s can still apply
• You are usually on a partner network, so speeds may not match what you are used to at home

When it makes sense:

Short trips within your roaming zone (EU to EU is the obvious one). When your plan already includes roaming data at no extra cost. Business trips where the company pays anyway. Weekend getaways where buying a SIM or eSIM is more hassle than it is worth.

Before You Decide

Before you pick an option, run through these:

• Do you need calls and SMS? If you just need data for maps, messaging apps, and browsing, most eSIMs and local data SIMs will do. But if you need actual phone calls or SMS (hotel bookings, local taxi services, two-factor authentication codes from your bank), you need a local SIM with a number, roaming on your home plan, or an eSIM that specifically includes one. Most digital eSIMs are data-only. That is fine for 90% of travelers, but make sure you are not in the other 10%.
• Do you need data immediately after landing? If yes, eSIM or roaming. Both work the second you turn off airplane mode. A local SIM means no data until you find a shop, and if you land at midnight or your connection is tight, that is a real problem. If you can handle being offline for an hour or two, a local SIM is fine. Download offline maps before you leave and save your hotel address as a screenshot. Old school but it works.
• How long are you staying? A weekend trip: roaming or a quick eSIM. A month: local SIM, every time. The per-gigabyte cost difference really stacks up over longer stays.
• How many countries are you visiting? One country: local SIM or local eSIM. Multiple countries in one region: regional eSIM. Random countries on different continents: you will probably end up mixing options, and that is totally fine.
• What does your home plan include? Check your roaming terms before you buy anything. You might already have free or cheap roaming and not even know it. No point buying an eSIM for a weekend in Spain if your plan already covers EU roaming.