You land in a foreign country, flip off airplane mode, and see your carrier sent you a welcome text. It's cheerful. It tells you international day passes are available for just $10 a day.
Ten dollars a day sounds reasonable until you do the math. A 10-day trip means $100 just to use the same data plan you're already paying for at home. That's before you've bought a single coffee.
For budget travelers, the answer is a local SIM or travel eSIM, and the price difference is way bigger than you'd think. Here's exactly how they work.
Your three options at a glance
| Option | Typical cost | Data | Setup | Best for |
|---|---|---|---|---|
| Carrier day pass | $5–$12/day | Your home plan allotment | None | Short trips, work travel |
| Local physical SIM | $10–$25 one-time | 5–30GB+ | Low (buy on arrival) | Budget trips of 5+ days |
| Travel eSIM (e.g., Airalo) | $5–$30 one-time | 1–20GB | Easy (buy before you go) | Tech-savvy budget travelers |
| International add-on | $5–$15/month extra | 0.5–5GB | None | Very light data users |
The math behind cheap international data
Let's use a 10-day trip to Europe as the example.
T-Mobile's International Day Pass runs $5 per day. AT&T and Verizon now charge $12. That's $50 to $120 for the trip, just for the privilege of using your existing plan abroad.
A travel eSIM for Europe covers the same 10 days with 5GB to 10GB of data for $15 to $25, depending on the provider.
For most travelers, the day pass math stops working after about two days.
How to buy a local SIM card while abroad
Buying a SIM when you land is the most straightforward route to cheap data. Most international airports have carrier kiosks right when you get off the plane. If you'd rather skip the airport markup, convenience stores and phone shops in the city carry the same SIMs—usually for less.
Expect to pay $10 to $25 for a local prepaid SIM. Most destinations will get you 10GB to 30GB of data for that price, which is a very different proposition than the 512MB you get from a T-Mobile day pass. The process takes about five minutes: find a kiosk, show your passport, and swap in the SIM.
Pros:
- Cheapest option, especially for longer trips
- Often includes local calls and texts
- Available almost everywhere
Cons:
- Requires an unlocked phone (more on that below)
- You'll have a temporary local number instead of your regular one
- You have to physically swap out your SIM card
Pro tip: Southeast Asia
Southeast Asia is in a category of its own. In countries like Thailand and Vietnam, tourist SIMs with generous data allowances routinely cost $5 to $15—sometimes less. If you're headed that direction, the local SIM choice is even more obvious.
How a travel eSIM gets you cheap international data
An eSIM works exactly like a physical SIM, except you download it to your phone instead of inserting a card. Airalo is the biggest name in the space, with plans covering more than 200 countries. You buy a plan in the app before you leave home, and it's active the moment your plane lands.
The big advantage is dual SIM capability. If your phone supports it, you can use your home SIM and the travel eSIM simultaneously. That means you're still reachable on your regular number for calls and texts while using local data rates for everything else. Our guide to the best eSIMs for international travel breaks down the top options right now.
Pros:
- No physical SIM swap required
- Buy and set up before you go
- Keep your home number active with a dual SIM
Cons:
- Requires a compatible, unlocked phone
- Can be slightly pricier than physical SIMs in some regions
Before you buy, confirm your phone actually supports eSIM. Most iPhones from the XS onward and the majority of modern Android flagship phones support eSIMs, but it's worth checking before you're standing in an airport with a dead data connection.
On Samsung Galaxy and most Android phones, go to Settings > Connections > SIM Manager.
On iPhone, go to Settings > Cellular. If the eSIM option isn't there, you'll need a physical SIM instead.
FAQs
Is it cheaper to buy a SIM card overseas?
Yes, buying a local SIM card overseas is almost always cheaper than using your home carrier's day pass. A local prepaid SIM typically runs $10 to $25 and covers far more data at the same price point. For any trip longer than two or three days, a local SIM or travel eSIM will save you money.
What's the difference between roaming and a local SIM?
With roaming, your home carrier borrows another network on your behalf and passes the markup on to you. A local SIM connects you directly to that country's network at local rates. The connection quality is similar—the price is not. Our guide on how international roaming really works has the full breakdown.
Can I use an eSIM and my regular SIM at the same time?
Yes, you can use an eSIM and your regular SIM at the same time if your phone supports dual SIM. You keep your home number active for calls and texts while the eSIM handles local data. Most modern iPhones and many current Android devices support this, but it's worth confirming before you travel. Our guide to global and travel SIM cards covers dual-SIM setups in more detail.
Do I need an unlocked phone to use a local SIM?
Yes, you do need an unlocked phone to use a local SIM card abroad. A locked phone is tied to your carrier and won't accept a foreign SIM. If you bought your phone outright or have finished paying it off, it's likely already unlocked. If you're not sure, call your carrier before you leave.
Scott Houghton
Jr. Staff Writer
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