When I moved to Japan in 2021, I signed up for a Docomo “gigaho” plan using an unlocked phone I brought from the US (a Moto G Stylus, 2020 edition). There were no issues. However, about a month ago, I realized that by switching to Ahamo I could save about 3000 yen/month. I finally got around to switching yesterday. I clicked through some screens warning me that my phone wasn’t “verified to be compatible,” but I had gotten similar warnings when I signed up for my initial Docomo plan. Because my device had worked for well over a year on Docomo, and because Ahamo was provided by the same parent company over the same network (and in theory, even using the same SIM), I figured there would be no issue.
I was wrong.
Today when I woke up, I found my phone with “No service – Emergency calls only” scrolling across the top. Clearly, there’s been some issue with the switching procedure. I looked through all historical posts I’ve been able to find about switching to Ahamo, and haven’t seen this problem appear before – so I decided to ask for help myself.
To fix it, so far I’ve tried:
1. Restarting, as well as taking the SIM card out and putting it back in.
2. Resetting the APN to factory default, as well as deleting all the APNs in my phone and re-entering it manually.
3. Making sure that VoLTE is enabled (it is, though it’s labeled in the settings as “4G Calling”)
For what it’s worth, on the “online Docomo account” side of things, the switch seems to have gone well, which hopefully means that I could go back to my old plan if necessary, if I can’t get this working.
Before I do, though, there are a few other steps which I’ve been thinking of taking. I’ve held off on these because they either seem “irreversible” to some degree, or would require additional money, so I wanted to ask for advice/experiences before proceeding with any of them.
1. First and most obvious is that using the Ahamo app on my smartphone, I can start a “開通” procedure. However, it does state that “the device I’m currently using will be rendered incapable of use” (the exact terms are “現在お使いの端末は使用できなくなります”), and it also seems like it’s designed for devices which have been bought from the Docomo store (which mine isn’t). Granted, my handset currently *is* “incapable of use,” but I’m concerned that this might make my situation worse somehow.
2. I can possibly request a new SIM. I’ve seen Ahamo-branded SIM cards delivered when people switch from different carriers, and this might help. However, it seems like the way to request one is through a centralized Docomo website, so this may not actually cause any difference. Also, it seems to cost 1100 yen, and I’m concerned this could somehow invalidate/override my current SIM which worked up until now, making it harder to go back if this all fails.
Has anyone found themselves in a similar situation before? Most other advice I can find states that the transition from Docomo to Ahamo went easily, and I haven’t been able to find another post with a similar issue. Am I overlooking something simple?