How do I increase the ring time before my iPhone 16 turns on voicemail?

It's set by your carrier, not by the iPhone. Contact them.

Mac-PC-Guy wrote:

I just successfully did this on my wifes Iphone and my own, iphone se and iphone 11. It's very simple to increase the ring time to 30 seconds before the voicemail answers. Go to settings-apps-phone-Live Voicemail. Turn off Live Voicemail and ring time will automatically change to 30 seconds. You may have to do this each time you update your software on your phone in case it goes back to default Live Voicemail "on". I got this information from my carrier but it's really an Apple issue in my opinion.

OK. What if someone wants Live Voicemail AND their phone to ring the maximum amount of time, like me? The carrier is the one who sets the time and the carrier can increase the time and the user, who might want Live Voicemail can still have it as well.

I just successfully did this on my wifes Iphone and my own, iphone se and iphone 11. It's very simple to increase the ring time to 30 seconds before the voicemail answers. Go to settings-apps-phone-Live Voicemail. Turn off Live Voicemail and ring time will automatically change to 30 seconds. You may have to do this each time you update your software on your phone in case it goes back to default Live Voicemail "on". I got this information from my carrier but it's really an Apple issue in my opinion.