Japan, who received their ratification at this week's ICC annual conference in London, join new affiliate members Jersey, Guernsey, Mali and Slovenia, taking the total membership of the ICC to 96 countries.
Japan, an affiliate ICC member since 1989, join Fiji and Papua New Guinea as associate members of the ICC EAP region, the EAP said in a statement on Thursday.
The region also has seven ICC affiliate members including Indonesia, Cook Islands, Vanuatu, Samoa, Tonga, South Korea and Philippines.
There are now 915 senior and 2,896 junior players playing in organised cricket activities in Japan with 22 grounds used for regular competition including a facility at the base of Mt Fuji, the EAP said.
ICC EAP regional development manager Tim Anderson welcomed the approval of Japan as an associate member.
"The ICC EAP Development Program is excited about working with the Japan Cricket Association as it now takes the development of cricket in Japan to the next level."
From September 23 to 29 Japan will be competing against Cook Islands, Samoa, Tonga, Indonesia and tournament hosts Vanuatu in the 2005 EAP Cricket Cup, a regional component of the ICCs World Cup qualifying series.