Based on literature records and the results of an extensive trapping program, presence records for 194 species of Bactrocera and Dacus in the 19 provinces of Papua New Guinea (PNG) are presented. Of the 770 records, over 500 are new. Based on species accumulation curves, Central, Morobe, Madang, Eastern Highlands, Western Highlands, New Ireland and Bougainville provinces, plus the province pairs of East and West Sepik, East and West New Britain, and Southern Highlands and Enga, can be regarded as having been adequately sampled. The remaining provinces should still be regarded as being under-collected. On mainland PNG, Morobe and Central provinces have the richest faunas and highest levels of endemism, approximately 15% each. All other mainland provinces have very low levels of endemism and are essentially subsets of the faunas of Morobe and Central Province. Although also with very low levels of endemism, the Highlands provinces have a statistically distinct fauna, suggesting that a pool of the PNG species are able to utilise both lowland and highland habitats. The fruit fly fauna of the island provinces is distinct from the mainland fauna, with further separation between the islands of the Bismark Archipelago (New Britain and New Ireland) and Bougainville. The greatest diversity of flies in PNG are associated with major northern geological elements, i.e., the New Guinea orogen, New Guinea accreted terranes and the off-shore islands, rather than the primary southern geological element, the Australian creton.