I can't use my Deta - Freetel SIM in Japan

[Satty2233]

I am using Japanese SIM Freetel. Before I changed my phone Xperia X Compact, I was able to use the Deta with the same SIM card with Sony's Aqua M4 in Japan. Now I can't connect Internet at all without connecting WiFi even I checked settings of mobil Deta by myself and also the FREETEL 's assistance but they said the problem may be caused by the Sony, the system of this phone. Then I called Japanese costomer Center but they said this product is made in overseas (model:F5321) so they can't tell anything for helping my problem. I am very disappointed about this issue. Please advise me if anyone know the solution. Thank you. 

[Emir1]

Hi @Satty2233, I am sorry to hear that.

It is very hard to answer market specific questions like this for me, as I am situated in Sweden and the standards may vary a lot. I do not have specific information about the Japanese market (this is where the Local support team can provide more specific answers), but I can do my best to help you find out!

First of all, in order to use your device in Japan, it has to have a Technical Conformity mark. Using global models without the technical conformity mark is prohibited in Japan, and you may be fined. The technical conformity mark is a sign of legal approval to use the device. It looks like this:

Check to see if your device meets this standard by going to Settings > About phone > Certificates, can you find the mark here?

If you have the mark, then the next step is to find out if the operator frequencies used by Freetel are supported in your device. To do so, we need to check the product information for F5321:
https://developer.sonymobile.com/downloads/whitepapers/xperia-x-compact-f5321-white-paper/

To summarize, it supports these frequencies:

Spoiler

UMTS HSPA+ 800 (Band VI), 800 (Band XIX), 850 (Band V), 900 (Band VIII), 1700 (Band IV), 1900 (Band II), 2100 (Band I) MHz GSM GPRS/EDGE 850, 900, 1800, 1900 MHz LTE (Bands 1,2,3,4,5,7,8,12,17,19,20,26,28,38,39,40,41) WLAN, 2.4G/5G, NFC

From here, I would recommend getting in touch with Freetel in Japan to see which frequencies they use, and they double check with the frequencies that your device supports to see that they're compatible.

Please check both of the above and let me know how it went!

[Satty2233]

Thank you very much for your prompt and warm message! Actually, I couldn't find the mark though... Can I go next step?

[Emir1]

Ah, that is unfortunate. Well, I am not situated in Japan so I do not know how the local routines may look like, but I do know that you may be fined for using a device which is not certified so I advice against it. My recommendation would be to try and get in touch with the local support in Japan to see if they may offer some more exact details as I'm afraid I am a bit limited when it comes to market specific information in Japan as I am based in Sweden.