Best eSIM for Japan and Korea: Complete Guide

Planning a trip that combines the neon-lit streets of Tokyo with the palaces of Seoul? Smart move. Japan and Korea make for one of the best travel pairings in Asia, but there's one critical thing you need to sort before you land: staying connected.

The good news? You don't need to fumble with multiple SIM cards, hunt down pocket WiFi counters at the airport, or rack up eye-watering roaming charges. The solution is simpler than ordering ramen: a regional eSIM that covers both countries.

What Is an eSIM and Why You Need One for Japan and Korea

An eSIM (embedded SIM) is a digital SIM card that lives inside your phone. No plastic card to swap out, no tiny ejector tool to lose, and no wondering if you inserted it correctly. You buy it online, scan a QR code, and you're connected the moment you land.

For travel between Japan and Korea, this matters more than you might think. These aren't countries where you can rely on finding free WiFi everywhere. Sure, Tokyo has decent public WiFi, but try navigating the subway in Osaka or finding your Airbnb in Busan without data. Not fun.

Plus, if you're hopping between both countries on a single trip (and you should, they're only a two-hour flight apart), the last thing you want is to deal with buying a new SIM card every time you cross a border.

The Best Regional eSIM: Holafly Japan and Korea Plan

We've tested plenty of connectivity options across Asia, and for Japan and Korea specifically, Holafly's regional eSIM is the clear winner. Here's why it actually works in practice, not just on paper.

Coverage That Actually Covers

Holafly's Japan and Korea eSIM runs on major local networks in both countries. In Japan, you're getting fast 4G LTE and 5G coverage (where available) that works seamlessly from Hokkaido to Okinawa. In Korea, the same story. Seoul, Busan, Jeju Island - you're covered.

The coverage is excellent in urban areas, which is where you'll spend most of your time. Mountains, remote rural areas, and deep countryside might see weaker signals, but that's true of any carrier. If you're hiking in the Japanese Alps or exploring remote Korean temples, expect some dead zones. But for 95% of travelers, you won't notice any issues.

Pricing That Makes Sense

Here's what Holafly's Japan and Korea regional eSIM costs with our exclusive discount code ADAMANDLINDS (5% off):

Use code ADAMANDLINDS at checkout for 5% off any plan.

The 7-day and 14-day plans hit the sweet spot for most travelers. A week in Tokyo and a week in Seoul? The 14-day plan costs less than two separate airport SIM cards and works the second you arrive.

When to Consider the Monthly Unlimited Plan

If you're planning to stay longer than 30 days, or if you're the type who burns through data faster than a video-streaming teenager, Holafly's new monthly plans make more sense than stacking 30-day regional plans.

Holafly's Travel Unlimited plans start at $49.90/month for 25GB (Light Plan) or $64.90/month for unlimited data (Unlimited Plan). Use code ADAMANDLINDS to save 10% on these monthly plans. Both include:

• Unlimited hotspot capability (share with your travel companions or multiple devices)
• One eSIM that works globally, including Japan and Korea
• A European phone number for receiving SMS
• Monthly billing you can cancel anytime (yes, you can cancel after just one month)
• Pay yearly and save 22%

The Unlimited Plan at $64.90/month is actually cheaper per day than the 30-day regional plan if you're staying more than a month. With the 10% discount using ADAMANDLINDS, you're paying even less. Plus, you get unlimited data and hotspot, which is perfect if you're working remotely or traveling with family who all need connectivity. And here's the key: you can cancel after a single month if you don't need it anymore, but the savings make it worth keeping if you're continuing to travel.

How to Set Up Your Holafly eSIM for Japan and Korea

The setup process takes about three minutes, assuming your phone supports eSIM technology (most phones from 2019 onwards do).

Before you leave home:

Purchase your Holafly Japan and Korea eSIM using code ADAMANDLINDS for 5% off. You'll receive a QR code via email within minutes.

Open your phone's settings and look for "Mobile Data" or "Cellular." The exact location varies by phone, but it's usually under Settings > Cellular > Add eSIM (iPhone) or Settings > Network & Internet > Mobile Network (Android).

Scan the QR code Holafly sent you. Your phone will download the eSIM profile. Don't activate it yet.

When you land:

Turn on airplane mode, then turn on WiFi to connect to airport WiFi. Go to your eSIM settings and activate your Holafly eSIM. Turn off airplane mode. Within 30 seconds, you should see the carrier name appear and data connection establish.

That's it. No hunting for a SIM card shop, no standing in line, no trying to communicate what kind of plan you need.

Real-World Performance: What to Expect

Speed matters, especially if you're navigating unfamiliar cities, translating menus in real-time, or keeping up with work while traveling. In Tokyo, Seoul, Osaka, and Busan, we consistently saw download speeds between 20-50 Mbps on 4G LTE, with 5G areas pushing 100+ Mbps.

That's more than enough for Google Maps, video calls, uploading Instagram stories, or streaming music while you explore. If you need to download a large file or stream 4K video, hotel WiFi is your friend, but for daily use, the speeds are excellent.

Battery drain is comparable to using a regular SIM. Your phone works slightly harder when searching for signal in weaker areas, but we didn't notice any meaningful difference compared to our usual battery life.

Japan and Korea Connectivity: What Makes It Different

Both Japan and Korea have world-class mobile infrastructure, but they're surprisingly not great with free public WiFi compared to places like Taiwan or Singapore.

In Japan: Major train stations and some convenience stores offer free WiFi, but it's often time-limited and requires registration. Tourist spots might have WiFi, but don't count on it. Having your own data is essential.

In Korea: Seoul has better public WiFi than Tokyo, but it's still spotty. Outside major cities, you're on your own. KTX trains (Korea's bullet trains) have WiFi, but it's unreliable. Having consistent data makes the difference between a smooth trip and a frustrating one.

Both countries are incredibly digitally integrated. Restaurant menus, museum information, even some temple explanations are available via QR codes and apps. Without data, you miss out on a lot of useful information.

Why eSIM Beats Other Options for Japan and Korea

Airport SIM cards are expensive, require waiting in line after a long flight, and mean you can't have two active phone numbers (useful if you need to receive calls on your home number). They also don't work across borders. If you fly Tokyo to Seoul, you need to buy another SIM.

Pocket WiFi devices need charging, take up space, add weight, and become one more thing to keep track of. They also typically cost $8-15 per day, which adds up fast. The Holafly eSIM at $28.40 for 7 days (with code ADAMANDLINDS) costs less than three days of pocket WiFi rental.

International roaming from your home carrier is the most expensive option by far, unless you're only checking email once a day. Most US and European carriers charge $10-15 per day for international roaming. That's $70-105 for a week. The eSIM costs $28.40.

Common Questions About Using eSIM in Japan and Korea

Can I keep my home number active?

Yes. The eSIM works alongside your physical SIM, so you can keep your home number active for calls and texts while using the eSIM for data. Perfect if you need to receive two-factor authentication codes or important calls.

What if I run out of data?

Holafly's Japan and Korea plans come with unlimited data, so this isn't an issue. But if you're using one of the global plans with data caps, you can top up through the Holafly app.

Does it work on the Shinkansen and KTX?

Yes, coverage on high-speed trains is generally good, though you'll hit brief dead zones in tunnels. This is true of any mobile service. Overall, you can stay connected for most of your journey.

What about using it as a hotspot?

The regional Japan and Korea plans support hotspot functionality, so you can share your connection with travel companions or connect your laptop. The monthly unlimited plans explicitly include unlimited hotspot.

Do I need a different plan for each country?

No, that's the entire point. One Holafly eSIM covers both Japan and Korea. Cross the border, and your phone automatically connects to the local network. No action needed from you.

Tips for Getting the Most from Your eSIM

Download offline maps before relying entirely on data.

Google Maps lets you download entire cities for offline use. Do this before you leave as a backup.

Set up the eSIM before you leave home.

You can install the eSIM profile at home and just activate it when you land. This way, if something goes wrong, you can contact Holafly support without being stranded without internet.

Check your phone compatibility.

Most iPhones from XS/XR onwards support eSIM. Most Android phones from 2019 onwards do too. Check Holafly's website for a full compatibility list.

Use WiFi calling for home calls.

If you need to call back home, use WhatsApp, FaceTime Audio, or your carrier's WiFi calling feature rather than making international calls. Your eSIM is for data, not voice calls.

Monitor your data usage in the app.

Holafly's app shows your remaining data and days left. Even with unlimited plans, it's good to keep an eye on things.

The Bottom Line on eSIM for Japan and Korea

If you're traveling to Japan, Korea, or (smart choice) both, getting an eSIM before you go is one of those small decisions that makes your entire trip smoother. No airport stress, no language barriers trying to buy a SIM, no wondering if you're getting ripped off.

Holafly's Japan and Korea regional eSIM works well, costs less than the alternatives, and you can have it set up before you even leave home. Use code ADAMANDLINDS for 5% off, and you're looking at reliable connectivity for under $30 for a week.

For longer stays or if you're planning to visit multiple regions, check out Holafly's monthly unlimited plans starting at $49.90. They work in both countries plus everywhere else you might wander, and you can cancel after one month if you don't need them anymore. Use code ADAMANDLINDS for 10% off the monthly plans.

The goal isn't to be glued to your phone while traveling. The goal is to have connectivity when you need it: finding that hidden ramen shop in Kyoto, navigating Seoul's subway without getting lost, or video calling home to show your family the cherry blossoms. An eSIM makes all of that simple.

Frequently Asked Questions

What is an eSIM and how does it work in Japan and Korea?

An eSIM is a digital SIM card embedded in your phone that doesn't require a physical card. For Japan and Korea, you purchase the plan online, receive a QR code, scan it with your phone, and activate it when you land. It connects to local networks in both countries automatically without needing to swap SIM cards at the border.

How much does an eSIM for Japan and Korea cost?

Holafly's Japan and Korea regional eSIM ranges from $6.55 for 1 day to $71.15 for 30 days when using code ADAMANDLINDS for 5% off. The most popular option is the 14-day plan at $45.50, which covers most travelers' needs for a two-week trip across both countries.

Can I use one eSIM in both Japan and Korea?

Yes, Holafly's regional eSIM covers both Japan and Korea with one plan. When you cross the border, your phone automatically switches to the local network without any action required from you. You don't need separate plans or SIM cards for each country.

Is eSIM better than pocket WiFi for Japan and Korea?

Yes, eSIM is more convenient and cost-effective than pocket WiFi. Pocket WiFi devices require charging, take up space, and typically cost $8-15 per day (over $100 per week). A Holafly eSIM costs $28.40 for 7 days with code ADAMANDLINDS, needs no charging, and works directly through your phone.

Does my phone support eSIM technology?

Most iPhones from XS/XR (2018) onwards and most Android phones from 2019 onwards support eSIM. Check your phone settings for "Add eSIM" or "Mobile Network" options, or visit Holafly's website for a complete compatibility list before purchasing.

Can I keep my home phone number active with an eSIM?

Yes, eSIMs work alongside your physical SIM card. You can keep your home number active for calls and texts while using the eSIM exclusively for data. This is perfect for receiving two-factor authentication codes or important calls while traveling.

What happens if I run out of data on my eSIM?

Holafly's Japan and Korea regional plans include unlimited data, so you won't run out. If you're using a capped global plan, you can purchase additional data through the Holafly app. For travelers staying longer than 30 days, the monthly unlimited plans starting at $49.90 offer better value.

Does the eSIM work on trains like the Shinkansen and KTX?

Yes, the eSIM works on high-speed trains in both countries. Coverage is generally excellent, though you may experience brief signal drops in long tunnels. This is normal for any mobile service and affects all carriers equally.

When should I activate my Japan and Korea eSIM?

Install the eSIM profile on your phone before leaving home, but only activate it when you land in Japan or Korea. This ensures you can troubleshoot any setup issues while still having your home internet connection available. Once activated, the plan duration begins counting down.

Can I share my eSIM connection with other devices?

Yes, Holafly's Japan and Korea eSIM supports mobile hotspot functionality, allowing you to share your connection with travel companions or connect your laptop. The monthly unlimited plans specifically include unlimited hotspot capability for connecting multiple devices simultaneously.

FTC Disclosure:

Look, we're going to be straight with you: some of the links in this post are affiliate links, which means if you click through and buy an Holafly eSIM, we get a small commission. Does this influence our recommendation? Sure, in the sense that we only partner with companies we actually use and trust. We've tested plenty of eSIMs across Asia, and Holafly is what we use for our own family travels. Your price stays the same (actually, it's cheaper with our code ADAMANDLINDS), we get a few bucks to keep this blog running, and you get reliable connectivity in Japan and Korea. Everyone wins, except maybe the airport SIM card kiosks.