In an effort to reduce cost and offer Pan India 3G service, Vodafone, Bharti Airtel and Idea Cellular have started sharing their networks to provide seamless service to their customers.

The three will now use each other''s networks through inter and intra-circle roaming arrangements where they do not have licences.

" Vodafone has entered into a bilateral roaming agreement, both inter and intra circle, with Idea and Airtel to provide 3G services to our customers in the circles where we have not built our own 3G network, in order to bring a pan-India experience of 3G services to our customers," Vodafone said in a statement.

However, nobody divulged the revenue sharing arrangement among the operators.

Roaming agreements - both inter and intra circle - are the norm in the Indian telecom industry since they help a service provider offer seamless service to its customers, the spokesperson added.

"Bharti Airtel has already started sharing networks for 3G services with each other. For example they are not having 3G network in Gujarat and have started using Idea's network to provide service in that area," an top official familiar with the matter said.

Airtel, Aircel and Reliance Communications each own 3G spectrum licence in 13 of the 22 telecom circles, while Vodafone has it in 10 circles and Idea and the Tatas in nine circles.

Idea has entered into an intra-circle roaming arrangement with Vodafone for introducing 3G services in Delhi and Kolkata circles while Bharti Airtel will partner Idea in providing 3G services in Karnataka - primarily in Bangalore and Mysore.