The Roman Catholic Diocese of Vanimo is a suffragan diocese in the Latin rite ecclesiastical province of the Metropolitan Archdiocese of Madang in Papua New Guinea, yet depends on the Roman Congregation for the Evangelization of Peoples.

Its cathedral episcopal see is the Holy Cross Pro-cathedral, in Vanimo in the province of West Sepik (Sandaun).

As per 2015, it pastorally served 37,765 Catholics (34.0% of 111,000 total population) on 26,000 km² in 13 parishes and 96 missions with 26 priests (8 diocesan, 18 religious), 43 lay religious (20 brothers, 23 sisters) and 14 seminarians.

(all Roman rite, initially foreign members of missionary congregations)

This article on a Roman Catholic diocese in Papua New Guinea is a stub.