Voicemail for first iPhone appearing on second iPhone

rebhunr wrote:

The other phone is not in use but active. Used as backup if primary damaged, lost. I'd rather it didn't receive texts or voicemails from primary phone because I don't normally monitor it.

Messages are completely different and in Settings > Apps > Messages > Send & Receive - you can check the number you want to receive messages, since both phones have different phone numbers.

But for Phone Calls, while calls will be received on the number which was called, voicemail and phone call lists will appear on both phones.

See this from Apple about using the same Apple Account on two iPhones --> Make sure that each family member has a unique Apple Account - Apple Support

In your situation, you're not sharing an Apple Account with another family member, but you are sharing the same Apple Account between two iPhones and your phones are doing what Apple designed them to do.

If you want to stop this behavior, you'll need to separate the phones into two Apple Accounts. This link was written by a Senior Forum Member, which would help you with that --> How to “unshare” an Apple ID - Apple Community

rebhunr wrote:

voice message appears on my second iphone, different number, but call was made to my first iphone

Main phone: iPhone 17. Backup: iPhone 14 Pro

If both phones share the same Apple Account, it doesn't matter which phone is called, the voicemail message should be on both devices. The phone which was called, should have rung. But if a message was left, it will appear on both phones. When two phones share the same Apple Account, even with each phone having its own phone number, voicemail and calls are shown on both devices.

imessages are sendt not to a device but to an appleID so if both use the same they will both get the messages unless you disabled imessage on the spare

what AI says

"o turn off iMessage on your iPhone, open Settings, tap Apps, select Messages, and then tap the switch next to iMessage to turn it off. If you are switching to a non-Apple phone or facing issues, you can also use Apple's Deregister iMessage web tool. [1, 2]

Steps to Turn Off iMessage

• Open the Settings app on your iPhone.
• 
  
• Scroll down and tap Apps.
• 
  
• Tap Messages.
• 
  
• Find the iMessage toggle and switch it to the off position (the green light will turn gray). [1, 2]

"

more

iphone disable imessage - Google-

about voice mail then it's not really a phone thing but a carrier things, which explains that it works even if your phone dies or are not of coverish

so for that I would reach out to your carrier about options as how to disable it

Is the other phone in active use, when that happens?

Apple usually sends notifications and updates to the recently-active gear first, then to the less-recently-active gear.