EasyTicket Heading overseas for summer vacation, and stuck on “what do I do about data?” To cut to the answer: for a short 3~7 day trip, eSIM is the easiest and cheapest option. Carrier roaming is expensive, a local SIM gives you plenty of data but means opening up your phone, and pocket Wi-Fi only pays off when you’re splitting it among several people. This article compares all four options, fees included, and breaks down exactly which one to pick based on your trip length and situation.
There Are 4 Main Ways to Get Data Abroad
Using the internet overseas breaks down into four options: ① carrier roaming ② a local/travel SIM (USIM) ③ eSIM ④ pocket Wi-Fi. Each works quite differently.
- Carrier roaming: Keeps your own number, and it just turns on the moment you land — no setup required. But it’s expensive. SKT’s flagship roaming plan, ‘baro,’ starts at 29,000 won for 3GB over 30 days (source: SK Telecom).
- Travel SIM: You take out your phone’s original chip and pop in a new one. Data is generous and fairly cheap, but you can’t receive calls or texts sent to your Korean number while you’re using it.
- eSIM: No physical chip — just scan a QR code and a digital SIM installs inside your phone. You can keep your own number for calls and texts while using the eSIM just for data, which is why it’s the most popular option these days.
- Pocket Wi-Fi: You carry around a palm-sized router that multiple devices connect to over Wi-Fi. In Japan, KT’s Roaming Egg runs about 3,000 won a day (speed capped after 5GB).
The key question is: “Do I want to keep my number while using cheap data?” If so, eSIM is the answer.
Comparing eSIM, Local SIM, Roaming, and Pocket Wi-Fi
Numbers make this easiest to see at a glance. Here’s a breakdown based on a one-week overseas trip.
| Option | Approx. Fee (7 days) | Calls/Texts on Your Number | Pros | Cons |
|---|---|---|---|---|
| Carrier roaming | About 29,000~79,000 won | ✅ Yes | Automatic, no setup | Most expensive |
| eSIM | About 15,000~25,000 won | ✅ Stays active | No chip swap, install ahead of time | Only on supported phones |
| Travel SIM | About 10,000~20,000 won | ❌ No | Plenty of data | Chip can be lost, number blocked |
| Pocket Wi-Fi | About 3,000~4,900 won/day | ✅ Separate phone | Shareable among a group | Device rental and daily charging |
For a 7-day trip to Japan, carrier roaming runs 77,000~105,000 won, while eSIM runs about 15,000~25,000 won. For the same trip, eSIM is usually 50~70% cheaper.
Roaming is convenient, but 70,000~100,000 won for a few days’ trip adds up. That’s why most short-term travelers these days are switching to eSIM.
How to Choose Based on Trip Length and Situation
“What’s best?” is actually the wrong question. The right answer depends on how many days you’re going, how many people are using it, and which country you’re visiting. Try mapping it onto your own summer vacation plans.
3~7-Day Short Trips (Solo or Couple) → eSIM
This is the most common case, and where eSIM shines the most. Install it at home ahead of time, then just switch it on when you land. Even unlimited plans run around 4,000 won a day, so it’s easy on the wallet.
Heavy Data Use or Long Stays → Local SIM
If you’re streaming video or tethering all day, or staying more than 2 weeks, a local SIM can work out cheaper per gigabyte. Just be prepared to miss verification texts sent to your Korean number during that time.
Families or Groups of 3+ → Pocket Wi-Fi
Splitting one device among several people drives the per-person cost way down. Dividing 3,000~4,900 won a day among 3~4 people is often cheaper than buying several individual eSIMs. The trade-off is that someone has to carry the device at all times and charge it daily.
If Setup Sounds Like Too Much Hassle → Roaming
If convenience matters more than price, roaming is a fine answer too. Carriers sometimes run discount promotions for first-time roaming users in their 20s~30s, so it’s worth checking the carrier’s app before you leave.
eSIM only works on supported phones. iPhones from the XR/XS onward and Galaxy phones from the S20 onward (excluding some unlocked and overseas models) generally support it. Check whether your phone supports eSIM before you pay for a plan.
How to Set Up eSIM (iPhone and Galaxy)
With just a QR code, setting up eSIM takes about 1~2 minutes — as easy as installing an app. Here’s how, by device.
iPhone
Settings→Cellular (Mobile Data)→Add eSIM- Scan the QR code from your provider, or enter the activation code
- Wait a moment for the profile download to finish
- Right after installing, leave that line set to OFF
Galaxy (Android)
Settings→Connections→SIM ManagerAdd eSIM→ scan the QR code or enter the code- Wait for the profile download to complete
Install it at home ahead of time and leave the line switched off. Turn on the eSIM line once you land at your destination airport, set calls/texts to your Korean number (the primary line), and set mobile data to the eSIM line — that way you still receive verification texts while using cheap data.
How to Avoid a Surprise Bill
Trying to save money can sometimes backfire into a surprise bill. Follow these and you’ll be safe.
- Turn OFF data roaming on your primary line — even if you’re using an eSIM, charges can still apply if data roaming is on for your Korean-number line.
- Set mobile data to the eSIM line — on iPhone, you need to switch the line selected for ‘Mobile Data’ to the eSIM.
- Turn ON data roaming for the eSIM line — the eSIM itself relies on the local network, so its roaming setting needs to be on to connect.
- Turn off automatic updates and cloud backup — this blocks large background data transfers.
- Confirm installation before you leave — install the profile at home in case you can’t get a QR code once you’re there.
Once an eSIM is installed, the QR code often can’t be reused. Deleting it by mistake makes reissuing a hassle, so don’t delete the profile until your trip is completely over.
Frequently Asked Questions (FAQ)
If I install an eSIM, how do I still get KakaoTalk verification texts?
Keep your primary line (Korean number) on and set calls/texts to that line, and verification texts will come through as usual. You only need to switch data to the eSIM, so there’s nothing to worry about. Just remember to turn off data roaming on the primary line.
For a Europe trip crossing several countries, do I need to buy a new one for each country?
No. There are regional eSIM plans that bundle multiple countries together, like Europe or Asia, so a single purchase works across several countries. Buying separately for each country actually costs more.
My eSIM plan is unlimited — why did it suddenly slow down?
Even “unlimited” plans often throttle your speed once daily usage crosses a certain threshold. Pocket Wi-Fi and local SIMs come with the same kind of “speed capped after X GB” condition. Be sure to check the speed-cap details before you pay for a plan.
I need internet the moment I land — will eSIM work for that?
If you install it ahead of time, switching on the eSIM line the moment you get off the plane connects you to the local network instantly. That’s why eSIM is especially convenient if you need maps or a taxi app right away.
To sum up, eSIM is the cheapest and most convenient option for most short overseas trips. If you’re a heavy data user, go with a local SIM; if you’re traveling in a group, go with pocket Wi-Fi; if setup sounds like a hassle, go with roaming. Check whether your phone supports eSIM before you leave, and install it at home ahead of time — and your data worries for this vacation are over.