I use CarPlay all the time with my iPhone, almost entirely in order to use navigation apps like Waze and Google Maps.   I nearly always connect the phone via a USB cable but sometimes, if it's a short trip, I don't bother and allow it to work over wireless CarPlay.

 

I would like my wife to be able to play music from her phone through the car speakers via bluetooth. 

 

Is this possible and easy?   I don't want to turn Bluetooth off on my phone as that would impact my Apple Watch, but if I don't do that, can my wife's still connect to play music, while I'm connected for navigation.

 

Any suggestions on this would be great.

 

I believe you can, though I have never used two iPhones in the scenario you mention. However, what I have done is connect my iPhone via CarPlay and my wife's Phone connects via bluetooth - incoming and outgoing phone calls use the car's mic and speakers. Also, whilst CarPlay is in operation, I can play music from a USB stick.

I see no good reason why you couldn't do what you describe.

Another thought - if you have Apple Music then you (or your wife) could play music with SharePlay (https://support.apple.com/en-gb/108767)

I'll have to have a play with it and see what works.   I do have most of our music on a USB stick in the car but the horrible UI on the Infotainment system makes it hard work to find and play music - even for a passenger who can concentrate on the screen, so playing music from her phone would be far easier for her.  

With two iPhones, my car connects CarPlay to the last one used (if it's within range) regardless of the Infotainment system user. Which ever one connects to CarPlay, the other with 'conventional' Bluetooth.

 

For music on the USB stick, I usually use voice control to request either the album name or artist name. I haven't [yet] added playlists but guess they'd work too.

I've had a quick play with this and it seems that I can indeed add another iPhone for bluetooth.  In fact, when I did so it (I mean Infotainment) asked whether I wanted also wanted to use it for phone and/or CarPlay;  I said no to both.  I was then able to listen to music from the second phone while using CarPlay with the first.

 

So I think I've answered my question but thank you all for the helpful posts here.