Apps like Localcast can stream media that you have on your phone to your Chromecast. The problem is, when internet access is available, it can still use mobile data for the connection.

How to use ChromeCast without WiFi in easy way|Tech-addict Jun 22, 2020 How to Use Chromecast Without Wi-Fi Apr 10, 2020

The actual Chromecast device requires WiFi. It will only work on WiFi (or if you have the Ethernet adapter that was sold, you can use it hardwired). If you’re using a hotspot on your phone, then of course it will use data.

Cast off the shackles of Wi-Fi. As of right now, an iOS or Android device has to be on the same Wi-Fi network as a Chromecast to cast video to it. But not for long. Google will roll out an opt-in

5 Methods To Use Chromecast Without WiFi (Tested Ways

Mar 06, 2020 How to Easily Use Chromecast without Internet - iStarApps Part 3: How to use Chromecast without internet via Travel Router. It is the best way to use Chromecast without internet for people who travel a lot. Travel routers are user-friendly and pocket-sized devices. These devices allow you to stream numerous devices without any disturbance.