The deal will allow Softbank to challenge KDDI for second place in the country’s wireless market.
Softbank had a 22.9% mobile subscriber share in June, which when combined with eAccess’ 3.2%, would bring the operator to 26.1% - within touching distance of KDDI’s 27.5%
It will also allow Softbank to lower network infrastructure costs having launched a new LTE network in September to coincide with the launch of the iPhone 5.
Softbank will likely be able to combine its LTE network with that of eAccess allowing it to achieve wider coverage more quickly and efficiently.
Softbank said that it aimed to complete the acquisition in February 2013.