A reader, Gary, asks

I recently bought a Galaxy S9 Plus (Verizon) to use on Straight Talk via Verizon towers. I am unable to use WIFI calling on it. I tried to set it up but the menu options I found online to activate it did not exist on my phone. I then went to Straight Talk’s website and ran the program to see if my SIM was WIFI calling capable. It came back negative, with instructions to call tech support for more information. So I called, and was told that WIFI calling was not available on Straight Talk via Verizon towers. But he said I could go to Walmart and buy a T-Mobile or AT&T SIM that would work for WIFI calling. But I don’t want to switch from Verizon as I had AT&T before and while traveling often had no signal. It’s the whole reason I switched to Verizon.

So I’m not sure whether to believe this guy or not. I was forced to switch phones because of CDMA going away on Verizon at year’s end, and I really need WIFI calling capability because I live in a location where an LTE signal is not reliable. If I can’t talk on Voice over LTE or WIFI, this phone is worthless to me while I’m at home.

Ugh. I have no idea what to do next.

If I could choose plans I’d go with Verizon just for the coverage. I had AT&T (through ST) in the past and often would not have service in the areas I travel. With Verizon I’m very rarely without coverage. Unfortunately, it’s just very weak at my home.
I’m on the one-year unlimited plan with Straight Talk. Unfortunately, I just re-upped it a week or so ago. Otherwise I would switch now. I got the S9+ on eBay, it’s locked to Verizon. I love the phone, just can’t believe I won’t be able to use WIFI calling with it while on ST. Maybe I’ll have to use Whatsapp or something for the next year until I can switch plans.

Hi Gary,
You are in a difficult position because Straight Talk has unreliable support for Wi-Fi calling and you have prepaid for one year of service in advance making changing carriers expensive.

Straight Talk offers service on the AT&T, Verizon, T-Mobile and Sprint networks but they only offer support for Wi-Fi calling on their T-Mobile network. In my experience it may work on their ATY&T network as well, but many people report not being able to get it to work. Your Verizon S9+ should be unlocked. You can verify that by borrowing an AT&T or T-Mobile SIM from a friend and trying it in your phone. If you can make a call, it’s unlocked. I took at quick look at the specs for your phone and it appears to be fully compatible with both the AT&T networks at least according to Frequency Check and assuming I checked for the correct model number.

Unfortunately, switching to Straight Talk’s ATT or TMobile’s towers, at best will get you Wi-Fi calling at home at the expense of worse coverage everywhere else you don’t have Wi-Fi. And you’ll have no idea if Wi-Fi calling will work until you try it. Its possible that the Verizon S9’s software may not support Wi-Fi calling on their ATT or TMobile towers due if Verizon has tweaked the software on their phones.

If it was possible to leave Straight Talk, your phone should be eligible for use with Verizon prepaid or Visible, both of which offer Wi-Fi calling. You will need to check the phone’s serial number of eligibility before signing up.

All this doesn’t leave you with many great options. you could spend $35 to activate an ST AT&T or T-Mobile SIM and see if Wi-Fi calling works. Spend the $2 for a couple of SIMs first and see if you at least get the options for WiFi calling first before paying for a plan. If it works, you could transfer your service to one of those networks.

You could also look into using Google Voice, you may be able to get that set up so you can get use Wi-Fi at home.

The other thing you should do is frequently try to enable Wi-Fi calling frequently. I suspect that at some point it will work when ST / Verizon fully convert to LTE, dropping CDMA. Supposedly, they are adding Wi-Fi calling to tracfone owned Total Wireless which also uses the Verizon network. I also keep thinking about how I was able to get Wi-Fi calling on my iPhone with Straight Talk’s ATT towers even when they said it would not work.

another thing some readers have told me is that those Verizon micro cells you plug into your wi-fi network for coverage at home, also work with ST Verizon phones. It may not be easy or cheap to get one.

The last option, I’d try, which is really a hack. Stick a Verizon SIM in your phone. (doesn’t need to be active) Find and turn on the options for Wi-Fi calling. and then stick your SIM back in the phone. Try enabling the options for VoLTE and HD-Voice on your phone.

sorry I don’t have any better options.