Help configuring for data-only SIM in Japan?

I’m traveling for 3 weeks in Japan and was planning to use a prepaid data-only SIM card while I am here. Unfortunately I am not having any success getting it to work and cannot contact the company tech support. So I am hoping someone on the forum will have some experience to share.

Phone: Samsung Galaxy S7 (herolte)
e OS version: 1.8.1-20230204257075

I purchased 2 prepaid SIM cards from the same company. They access the IIJ cell network. We put one in my daughter’s iPhone 6 and had little trouble getting it to work. After many attempts mine is still not working.

To use the card you have to configure the APN settings. After poking around I figured out how to do this on e OS, but still cannot get data. The instructions call for the following to be set:

User name
authentication type

I’ve done all that but had to leave all the other settings in the APN configuration alone, because the instructions don’t say what to do with them.

Also, I notice that microG services is crashing more since I inserted the data-only sim; though I don’t know if this is related.

I hope someone can offer some advice. The card is non-refundable and I really need access to data, because wifi is not widely available in Japan.


Regain your privacy! Adopt /e/ the unGoogled mobile OS and online servicesphone

Usually, you only make the APN entries that the provider specifies, and leave everything they don’t mention empty.

I’ve used some international data SIMs, and I’ve noticed that it can sometimes take several minutes for the network to establish. With /e/OS, I also have to first connect to 2G only before then switching to 4G LTE. (I think this might work even if there’s no 2G available, but I’m not certain.)

I don’t know how long you’ve waited for it to connect, or whether you’ve rebooted the phone after inserting the SIM, but if not, you might try it.

(And also make sure the APN setting is saved and that it’s selected, but I’m guessing you know that already.)


What about radio band used in Japan ?
The phone is it compatible ?

In general it should work, I have used last november one with a FP3. Did not need to set any APN since it was available. I think mine was Softbank

Thanks for the tip! I tried switching to 2G and then 4G as my preferred network speed and it suddenly worked!


No problem; glad it worked for you.
To make things easy for the rest of your trip, you might want to switch to 2G before shutting down the phone or when entering large buildings where you don’t expect to have a signal. Then upon restart or when exiting the building, you can switch back to LTE without hassle.

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