BSNL is the best network for Char Dham Yatra. It is available in all the four Dhams. Airtel also works well. However, there are chances of not getting the connection everywhere. Apart from these two, you can also opt for Idea and Vodafone. It is recommended not to use Jio and other similar networks.
It is best to carry a BSNL sim as the other networks don’t work properly in the Char Dhams and the major cities.
As the Char Dhams of this Yatra are located in the Himalayan terrain, you will lose network at many places. However, these networks work the best among all.
The more you travel and go towards the elevation, the chances of losing the network connectivity increases. As you move towards the city like Rudraprayag, Uttarkashi etc, you will get back the network connection.