Setup Guide
How to Set Up APN Settings in Japan (iPhone & Android)
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If you only read this part
If your Japan SIM is in but there's no data, the usual cause is a missing APN (Access Point Name) — the setting that tells your phone how to reach the data network. Get the correct values from your carrier's welcome email or website, then enter them on your phone.
On iPhone, it's often automatic; if not, check Settings → Cellular → Cellular Data Network. On Android, go to Settings → Network → SIMs → Access Point Names. When in doubt, restart the phone — it fixes most activation issues.
Section 01
What an APN is, and why it matters.
An APN — Access Point Name — is the small piece of configuration that tells your phone how to connect to your carrier's mobile data network. Think of it as the address your phone dials to reach the internet over cellular. Get it right and data just works. Get it wrong, or leave it blank, and you'll have signal bars but no data — the single most common reason a new Japanese SIM appears "dead."
Modern phones often set the APN automatically when you insert a supported SIM or install an eSIM. But "often" isn't "always," especially with budget brands and foreigner-focused providers. When automatic setup doesn't happen, you enter the APN by hand. It takes two minutes once you know where to look.
Section 02
First: get your carrier's APN values.
Before touching settings, find the correct values. Do not guess them — wrong values won't work and will waste your time. They come from your carrier:
- Your welcome email or SIM instructionsMost carriers include the APN, username, and password in the email or printed insert that comes with your SIM or eSIM.
- The carrier's websiteSearch the carrier name plus "APN settings." Foreigner-focused providers like Mobal and Sakura Mobile publish clear English instructions.
- The activation portalFor eSIMs, the activation page or app usually shows the APN under a settings or setup tab.
You're typically looking for three things: the APN name (e.g. something like plus.acs.jp — but use your carrier's actual value), and sometimes a username and password. Some carriers also specify an authentication type like CHAP or PAP.
Section 03
iPhone: step by step.
Try automatic first
Insert the SIM or install the eSIM, make sure you have signal, and restart the phone. Often the iPhone configures itself and data starts working with no manual step.
Check mobile data is on
Settings → Cellular (or Mobile Data). Make sure Cellular Data is on, and if you have multiple lines, that the Japan SIM is selected for data.
Install a carrier profile if provided
Some carriers give you a configuration profile to download. If yours does, open the link in Safari and follow the install prompts. This sets the APN for you.
Enter the APN manually if needed
Settings → Cellular → Cellular Data Network. If the field is editable, enter the APN, username, and password your carrier specified under the "Cellular Data" section. If you don't see this menu, your carrier likely uses a profile instead.
Restart and test
Restart the phone, turn off airplane mode, and open a website. If it loads, you're done.
Section 04
Android: step by step.
Open APN settings
Settings → Network & internet (or Connections) → SIMs → choose your Japan SIM → Access Point Names. Menu names vary slightly by manufacturer.
Add a new APN
Tap the menu (often a "+" or three dots) and choose "Add" or "New APN."
Enter the values your carrier gave you
Fill in the APN name and the APN itself, plus username, password, and authentication type if your carrier specifies them. Leave fields blank only where the carrier says to.
Save and select it
Save the APN, then make sure it's the selected (active) APN — there's usually a radio button next to it.
Restart and test
Restart the phone, confirm mobile data and (if needed) data roaming are on, turn off airplane mode, and load a website.
Section 05
Still no data? Work through this list.
- Restart the phoneThis alone fixes a large share of activation problems. Do it before anything more complicated.
- Confirm the SIM is actually activatedSome carriers require activation before data works, and eSIMs can take an hour or two after sign-up. Check your activation status.
- Check mobile data and data roamingBoth can block data if set wrong. Make sure mobile data is on and the correct line is selected; some setups also need data roaming on.
- Make sure airplane mode is offObvious, but easy to miss — and toggling airplane mode on then off can also force a fresh network connection.
- Verify your phone is unlocked and supports Japan's bandsA carrier-locked phone, or one that doesn't support Japan's LTE bands (1, 3, 19, 28), won't connect properly. See our main SIM guide for band details.
- Contact your carrier's supportIf all else fails, foreigner-focused providers like Mobal and Sakura Mobile offer English support to walk you through it.
Setting up a SIM for the first time? Our main guide to getting a SIM in Japan covers the whole process, and eSIM vs physical SIM helps you pick the format that's easiest to set up.
FAQ
Frequently asked questions
What is an APN?
APN stands for Access Point Name. It's the setting that tells your phone how to connect to your carrier's mobile data network. When you insert a new SIM or install an eSIM, your phone sometimes configures the APN automatically — but when it doesn't, you have no mobile data until you enter it manually.
Why isn't my Japan SIM getting data?
The most common reason is a missing or incorrect APN. Other causes include the SIM not being activated yet, mobile data being switched off, the phone being carrier-locked, airplane mode being on, or the phone not supporting Japan's network bands. Check the APN first, since it's the most frequent culprit.
Where do I find the correct APN settings?
Your carrier provides them. They're usually in the welcome email or instructions that come with your SIM or eSIM, and on the carrier's website. Foreigner-focused providers like Mobal and Sakura Mobile include clear English APN instructions. Don't guess the values — use the ones your carrier specifies.
Do iPhones configure the APN automatically?
Often, yes. iPhones frequently pull the correct carrier settings automatically once a supported SIM is inserted and you're connected. When automatic configuration doesn't happen, you may need to install a carrier profile or, in some cases, the APN field appears under Cellular Data Network for manual entry.
My APN is correct but still no data — what now?
Restart the phone first; this resolves a large share of activation issues. Then confirm the SIM is activated, mobile data and data roaming are set correctly, airplane mode is off, and the phone is unlocked. If it still fails, contact your carrier's support — for foreigner-focused providers this is available in English.
Do I need to change the APN if I switch carriers?
Yes, usually. Each carrier has its own APN. If you switch from one SIM to another, your phone may need the new carrier's APN to get data. With an MNP number transfer, you still install the new SIM and set its APN if it isn't configured automatically.