Force iphone to use data when wifi has no internet?

"I know that you can tether a PC to the phone to use the phone's cellular internet connection but can you tether a phone to the PC to use it's Wi-Fi internet connection? Doesn't seem possible but what do I know."

Re-read the post I was replying to. He meant supplying internet access FROM the computer TO THE PHONE using WiFi

Copied from my initial post:

You cannot use your Wi-Fi connection for Internet connectivity while other devices are using Wi-Fi for Personal Hotspot. You can share only a cellular data connection; you cannot share a Wi-Fi connection. You need another iOS device to make this work.

Plan Z (definately not Plan 9) would be to get another iOS device (iPad), use the iPhone as a WiFi hotspot, and use the iPad to run Pandora and AirPlay. Other than getting Internet service at your location, there is no other possibility.

I have the same issue. fucheenogad needs to be simultaneously connected to a specific wifi connection for purpose other than Internet, and obtain internet through cellular data connection. If I am correct and the respective network hardware components are completely independent, then I assume requirement could be resolved with software update. That said, I’ve yet to take time to try Apple support session. This should be an increasingly common problem with use cases for ad hoc wifi networks increasing all the time.

This is an old thread, but I thought I'd post because there's an easy solution to the problem that was not mentioned. You do not have to use tethering or any additional equipment. However, it helps to understand IP routing and addressing.

Connect to the WiFi network in the settings app and press the info (letter "i" in a circle) button next to the network name. The network is most likely to set to DHCP mode, in which the IP address is automatically assigned. You are going to switch it to Static mode, where you specify the configuration by hand. But before you do that, make a note of the IP Address and Subnet Mask fields. Usually, they'll be something like 192.168.0.5 and 255.255.255.0.

Tap the Static tab and enter the IP Address as X.X.X.200, where the X's are the numbers you wrote down from DHCP mode. For example, instead of 192.168.0.5, enter 192.168.0.200. This should prevent your static address from conflicting with other devices' auto-assigned addresses. In addition, replicate the same Subnet Mask from DHCP mode exactly.

Here's the trick: make sure the Router and DNS fields are completely blank. This will tell the iOS device that there is no Internet connection.

With this configuration, the iOS device will use the cellular network for Internet connectivity and the local WiFi network for local destinations such as speakers. Exactly what you want.

G Snyder TOPPP you are a genius!!!

work perfectly with my ezcast for my car...I searched on internet the way to have bot airplay working and internet connection with cellular.

thank you very much for the clear explanation!

bye bye from Italy!