In a statement, the two companies said they would seek to expand collaboration to provide solutions for other customers globally.
Both companies have a strong background in research and development and this is expected to help in catering to other markets.
Tango Matsumoto, executive vice-president and head of Network Business Group at Fujitsu, said: "Through this partnership with Ericsson, we will provide flexible 5G network systems that are open and standard compliant, and will leverage our expertise in wireless technologies and network integration to a wide range of customers in and outside of Japan.
Fredrik Jejdling, executive vice-president and head of Business Area Networks at Ericsson, said: “Our global expertise in 5G combined with our understanding of the local market puts us in an excellent position to support the introduction of 5G in Japan.
"By working closely with operators and partners, we are creating solutions that will bring successful use cases and applications to the market. With Fujitsu we get an excellent partner to accelerate this development.”