Q: Wifi Password sharing between iOS devices.

No, not wifi passwords.

Are my existing saved passwords, Wi-Fi networks, and Internet accounts included in iCloud Keychain?

Yes. When you turn on iCloud Keychain, any previously-saved website usernames and passwords, Wi-Fi networks, and Internet accounts are automatically included in iCloud Keychain.

iCloud: Frequently asked questions about iCloud Keychain

I have known you to be correct every time - can you explain that? Am I misreading something?

My own experience has has been that it doesn't sync wifi network passwords.  If, for example, I go to my iPad and disconnect from my wifi choosing forget this network and then try to rejoin I am prompted to enter the password manually even though I have iCloud keychain enabled on all my devices and the same wifi network is joined on my iPhone.  Works the same way in reverse (forget network on iPhone but still connected on iPad, then try to rejoin on iPhone).  It makes me wonder what exactly is saved in the keychain when it says "wifi networks".  I should probably call support on this to get clarification.

Ok, your question prompted me to test this some more and I was eventually able to get it to work.  So iCloud keychain will sync wifi passwords across devices as suggested in the support article.  What I found is that tapping forget this network negates the keychains ability to sync the password even though it's properly configured on another device sharing the same keychain (i.e., forgetting the network takes precedence over the iCloud keychain).  When I joined a new network one device, however, I found that I was able to join the new network on another device sharing the keychain without being prompted for the password.

randers4 wrote:I should probably call support on this to get clarification.

Thank you again Randers for not only providing us with correct answer, but also invaluable entertainment for today.

I have created an app for this purpose. It's called WiFi Share.

Here is the link: https://itunes.apple.com/us/app/wifi-share/id961336021?ls=1&mt=8

It works on both iPhone and iPad, and soon will be available for OSX also.

I came across this thread and after reading @randers4 response, I tried again.  My iPhone is connected to a wifi network with a complex password. 

• I connected my iPad to my iPhone's hotspot so that keychain would update on my iPad.  Still couldn't connect to the wifi network.
• I then disabled keychain on the iPad and re-enabled it. 
• I reconnected to the iPhone's hotspot and shortly after tried the local wifi network.

At that point it worked. It seems that the iPad was not updating the keychain properly.

I checked into a hotel and had my Macbook Air connect the the wifi network. Then I looked at my iPhone and it automatically joined the same wifi network without asking for the password again.

Thanks for the post.  I wonder if Keychain info does not update dynamically.

I generally connect to networks with my iphone first, and figured it would be nice to get that same connection to automatically update to my ipad as well.  It did not work at first, but after following your instructions (disable keychain on ipad, then re-enable keychain) - my ipad connected to the wifi network desired automatically.

Thanks!

with sharing, i find my computer connecting to a wifi network thats not my home wifi (when i am at home). the network it connects to is a wifi hotspot that i often use elsewhere (like optimum or xfinity). is there a way to prevent my devices from connecting to it automatically ?

when im at home i want to connect to my home wifi.

I could not get the wifi password to transfer between an iPad and iPhone. My fix was the same as Windstorm. Switching the iCloud keychain off, connecting the iPad to the Wifi, then switching iCloud Keychain on again resulted in an update to the keychain and allowed the iPhone to access the Wifi password without having to enter it into the iPhone. There seems to be a glitch in the syncing of data. This is with iOS 9.2, so the problem appears to be persistent across iOS Builds.

My iPad and iPhone are doing this and I wish I could make it stop

not good for OS X at this moment.