eSIM Japan: Common Problems and How to Fix Them

TL;DR

Most eSIM problems in Japan can be fixed in under 2 minutes. The most common causes: data roaming isn't enabled, the eSIM isn't selected for cellular data, or the QR code was scanned on the wrong screen. Before panicking at Narita airport, check these three things. This guide covers the 8 most common problems — with a diagnosis and step-by-step solution for each.

1. "No network" / no signal upon arrival in Japan

This is the number one problem reported by travelers. You land at Narita or Haneda, activate your eSIM... and nothing. The iPhone shows "No Service" or "Searching." Don't panic — in 90% of cases, the fix takes 30 seconds.

Diagnosis

The problem almost always comes from data roaming. Depending on the type of eSIM and provider, this setting must be enabled or disabled:

• eSIM with a local Japanese profile (like PlanJapan, NTT Docomo network) → data roaming must be enabled
• Regional or global eSIM (some Airalo, Saily plans) → check the provider's instructions, the setting may vary

Step-by-step solution (iPhone)

1. Go to Settings > Cellular
2. Tap your Japan eSIM line
3. Enable "Data Roaming"
4. Go back and verify your eSIM is selected for "Cellular Data"
5. Wait 15 to 30 seconds — the network should appear

Step-by-step solution (Android / Samsung)

1. Go to Settings > Connections > SIM Card Manager
2. Select your Japan eSIM
3. Enable "Data Roaming"
4. Verify your eSIM is set as "Mobile Data"
5. Wait 15 to 30 seconds

If the network still doesn't appear: toggle airplane mode on for 10 seconds, then off. This forces the phone to search for a new network. If the problem persists, restart your device.

For a complete activation guide, check our iPhone eSIM activation tutorial or our Android and Samsung eSIM guide.

2. eSIM installed but no internet data

Your eSIM is installed, the network is visible (you can see "NTT Docomo" or "JP Docomo" in the status bar), but you can't load a web page or use Google Maps. This problem is very common on dual-SIM phones.

Diagnosis

Your phone is probably using your home SIM for data instead of the Japanese eSIM. On recent iPhones and Androids with dual SIM, the phone doesn't automatically switch to the new eSIM for cellular data.

Solution (iPhone)

1. Go to Settings > Cellular
2. Tap "Cellular Data" (at the top of the screen)
3. Select your Japan eSIM (not your home line)
4. Disable data on your home SIM to avoid roaming charges

Solution (Android)

1. Go to Settings > Connections > SIM Card Manager
2. Under "Mobile Data", select your Japan eSIM
3. Disable the home line for data

Tip: make this change before departure, while you're still on WiFi at home. That way, you just need to enable the line upon landing.

3. Slow or unstable connection speed

Your eSIM works, but pages load slowly. Instagram stories take 10 seconds to load, Google Maps lags behind your movements. Several possible causes.

Diagnosis and solutions

a) You've exceeded your data allowance (fair use)

Some providers throttle speeds after a daily consumption threshold — even on "unlimited" plans. Speeds drop to 128 or 256 kbps, barely enough to send a text message.

Solution: check your usage in phone settings (Settings > Cellular on iPhone). If you're approaching your limit, switch to WiFi for data-heavy tasks. At PlanJapan, data plans (10, 20, 50 GB) run at full speed until the last byte — no progressive throttling.

b) Wrong network band selected

Your phone may latch onto a less efficient network band, especially in transition zones between 4G and 5G.

Solution:

1. Toggle airplane mode on for 10 seconds, then off
2. If the problem persists, force 4G/LTE: Settings > Cellular > Cellular Data Options > Voice & Data > LTE
3. As a last resort, restart your phone

c) Low coverage area

Even though NTT Docomo covers 99% of Japan, some isolated areas (deep tunnels, remote islands, mountains) may have weak signal.

Solution: the situation is temporary. As you move, coverage returns. On the Shinkansen, the signal usually restores when exiting tunnels.

4. QR code won't scan

You're trying to scan the QR code received by email to install your eSIM, but the camera doesn't recognize it. Or you receive an error message like "Invalid eSIM" or "Unable to activate cellular plan."

Diagnosis

• Screen too small or brightness too low — a QR code displayed on a phone is often too small for another phone's camera to read
• Zoomed or distorted QR code — a cropped screenshot or poorly displayed PDF can be unreadable
• Unstable WiFi connection — installing the eSIM profile requires Internet

Solution: use the manual method

If scanning fails, you can always enter the activation code manually:

On iPhone

1. Go to Settings > Cellular > Add eSIM
2. Tap "Enter Details Manually"
3. Enter the SM-DP+ address and activation code provided in your email

On Android

1. Go to Settings > Connections > SIM Card Manager > Add Mobile Plan
2. Tap "Enter code manually"
3. Enter the full activation code (starting with LPA:1$...)

Tip: if you didn't receive a separate activation code, copy the full URL below the QR code in your confirmation email. It contains the same information.

5. eSIM disappeared after an iOS / Android update

This is a less frequent but particularly stressful problem: after a system update or restart, your eSIM has disappeared from the cellular plan list. No network, no data.

Diagnosis

System updates can, in rare cases, remove the eSIM profile — especially major updates (e.g., iOS 17 to iOS 18). This is a known bug from Apple and some Android manufacturers.

Solution

1. First check if the eSIM is still there: go to Settings > Cellular. If you see your eSIM line but it's disabled, simply re-enable it.
2. If the eSIM has disappeared: you'll need to reinstall it. Find the original email containing your QR code and repeat the installation procedure.
3. If the QR code has already been used and reinstallation fails, contact your provider's support to get a new eSIM profile issued.

Prevention: never do a system update during your trip to Japan. Postpone iOS/Android updates until you return. Go to Settings > General > Software Update > Automatic Updates and temporarily disable them.

6. Hotspot / tethering doesn't work

You're trying to share your connection with a laptop or a travel companion's phone, but the hotspot won't activate or devices can't connect.

Diagnosis

• Provider blocks hotspot: some eSIM plans (notably Holafly) limit or block tethering. Check your plan's terms.
• Incorrect APN settings: on some Android devices, hotspot requires specific APN configuration.
• Wrong data line selected: the hotspot uses the line set for "Cellular Data" — if it's your home SIM, the hotspot won't work with your Japan eSIM.

Solution (iPhone)

1. Verify your eSIM is selected for "Cellular Data" (Settings > Cellular)
2. Go to Settings > Personal Hotspot
3. If the option is grayed out, restart your iPhone
4. If the problem persists, reset network settings: Settings > General > Transfer or Reset > Reset > Reset Network Settings

Solution (Android)

1. Check APN settings: Settings > Connections > Mobile Networks > Access Point Names
2. Make sure the APN for your Japan eSIM is correctly configured
3. Select your eSIM as the "Mobile Hotspot" source
4. Restart the phone if needed

Good to know: at PlanJapan, tethering is included with no restrictions on all plans. If you have network, the hotspot works — no extra APN configuration needed on iPhone.

7. Specific issues on Google Pixel (Pixel 9 / Pixel 10)

Google Pixel 9 and Pixel 10 are excellent phones, but several users report specific difficulties with travel eSIMs in Japan. These problems are related to Google's software, not the eSIM itself.

Known issues

• eSIM profile installation failing with "Unable to download eSIM profile" message
• Intermittent signal loss after a network change
• eSIM not recognized after restart

Solutions

1. Update your Pixel — Google regularly fixes eSIM bugs in monthly security updates. Check in Settings > System > System Update
2. Clear the SIM app cache: Settings > Apps > Show System Apps > SIM Toolkit > Clear Cache
3. Reset network settings: Settings > System > Reset Options > Reset Network Settings
4. Try manual installation rather than QR code scanning — some Pixels have issues with QR code recognition via the camera

Tip: if you have a Pixel and are traveling to Japan soon, install your eSIM a few days before departure (while you're still on WiFi) to have time to resolve any issues stress-free.

8. eSIM doesn't work in the subway or Shinkansen

You have network on the surface, but the connection drops as soon as you enter the Tokyo subway or certain Shinkansen segments.

Diagnosis

This is normal behavior, not an eSIM problem. Tokyo's subway runs largely underground, and even Japanese domestic carriers don't cover 100% of tunnels. However, the situation improves every year.

What works

• Subway stations: almost all platforms and station halls have 4G coverage
• Shinkansen: continuous coverage on most lines (Tokaido, Sanyo, Tohoku), with brief drops in some tunnels
• Tokyo subway: coverage in stations, but intermittent signal in tunnels between stations

Practical tips

• Download your Google Maps routes offline before entering the subway
• Use the Japan Transit or Navitime app — they work partly offline
• Take advantage of stations to load your pages and messages before heading into the tunnel

Frequently asked questions

My eSIM won't connect to the network in Japan, what should I do?

Check these 3 things in order: (1) data roaming is enabled, (2) your eSIM is selected for "Cellular Data," (3) toggle airplane mode on and off. If the problem persists after a restart, contact your provider's support.

Can I use my eSIM and my home SIM at the same time?

Yes, that's exactly the advantage of dual-SIM. You can keep your home number to receive texts (bank verification, for example) while using your Japan eSIM for data. Go to Settings > Cellular and assign each line to its function (calls, texts, data).

Should I delete my eSIM after my trip to Japan?

It's not mandatory. The eSIM stays stored on your phone and doesn't consume anything once expired. You can leave it for your next trip or delete it to free up space if you've reached the eSIM profile limit (between 5 and 20 depending on the model).

My eSIM works in Tokyo but not in rural areas, is that normal?

It depends on the network your eSIM uses. eSIMs on the SoftBank network have limited coverage outside major cities. The NTT Docomo network (used by PlanJapan) covers 99% of Japanese territory, including Hokkaido, Okinawa, the Japanese Alps, and rural areas. If you have recurring coverage issues outside Tokyo, your eSIM is probably on a less extensive network.

How far in advance should I install my eSIM before departure?

Install your eSIM 1 to 3 days before departure, while you're still on WiFi at home. Installation requires an internet connection, and doing it in advance gives you time to resolve any issues. Most eSIMs only start their validity period upon first connection to the Japanese network — not upon installation.

My eSIM plan ran out mid-trip, what should I do?

You can buy a new eSIM and install it on your phone (recent iPhones support up to 8 eSIM profiles). At PlanJapan, delivery is instant by email — you receive a new QR code in minutes, even mid-trip. Also consider monitoring your usage in Settings > Cellular to anticipate.

Our recommendation

Most eSIM problems in Japan come from three simple mistakes: data roaming disabled, wrong line selected for data, or installation attempted without WiFi. If you prepare your eSIM before departure and follow the steps in this guide, you'll have network as soon as you step off the plane.

For a stress-free trip, we recommend choosing an eSIM on the NTT Docomo network (the best coverage in Japan, including rural areas and the Shinkansen) with a generous enough plan so you don't have to worry about usage:

• 1 to 2 week trip, standard usage → eSIM Japan 50 GB (Docomo network)
• Long trip, hotspot, or zero stress → eSIM Japan Unlimited

Install it 1 to 3 days before departure, check your cellular data settings, and enjoy Japan connected.