Domestic visitors in town for the Expo are concerned about roaming surcharges on their cell phones imposed by China Mobile, one of the three carriers in China and one of the two officially designated communication providers for the Expo.

Zhou Wenjie, an Expo visitor from Dalian, a coastal city in Northeast China's Liaoning Province, told the Global Times Monday that he is planning to purchase a new SIM card to register with a local mobile provider in order to avoid potential roaming charges.

"I will be staying here for a couple of weeks. I will buy a Shanghai SIM card because the national roaming charges are quite expensive," said Zhou.

Currently, China Mobile charges out-of-town subscribers with a capped domestic roaming fee of 0.4 yuan ($0.06) per minute for incoming calls and 0.6 yuan ($0.09) for outgoing calls. The provider has been gradually reducing the charges nationwide since March 2008 as required by the state telecommunication authorities.

According to the China News Service, there were around 80,000 inbound China Mobile subscribers from other provinces of the nearly 200,000 users in the Expo site, on May 1 as of 1 pm.

The mobile provider installed 17 cell towers and more than 200 cell stations along the streets in and around the Expo site and added nearly 50 mobile communication vehicles to enhance its reception in the Expo site, claiming that the mobile service provider is now capable to meet the need of 800,000 people, the Oriental Morning Post reported.

National mobile network operators throughout China are running their businesses with different provincial subsidiaries, a main cause of domestic roaming fees.