Under the agreement signed Wednesday, they will use each other’s base transceiver stations (BTSs) and sites for setting up more infrastructure like masts.

Hoang Minh Cuong, director of the Vietnam Telecommunications Authority (VNTA), said the sharing would help all of them save costs.

Cao Duc Thang, deputy general director of military-owned Viettel Group, said since nearly 100 percent of the population has coverage, competition for infrastructure is not a priority for networks.

But that would change with 5G, he said, pointing out that for 5G network coverage and achieving the goal of taking 5G to less populated areas, sharing telecom infrastructure would be crucial.

Thiem Cong Nguyen, deputy general director of MobiFone Corporation, said sharing BTS infrastructure has long been in the company's plans.

Nguyen Truong Phi, general director of Gtel Mobile, said with only a 2G network at the moment his company’s partnership with the other three is important for its future 5G development plans.

VNPT and Mobifone signed an agreement in May to share 700 locations and work together in a number of localities.