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The Bird’s Head region of West Papua is dissected by several major strike-slip faults, namely the Sorong, Ransiki and Yapen faults. Although the age and current activity of these faults is disputed, it is generally accepted that they were initiated within the last 23 million years. Several sedimentary basins, including the Biak Basin, filled largely by Cenozoic (mainly Neogene) carbonates, are found in close proximity to these faults, indicating a potential genetic link between faulting and basin formation. The Biak Basin is situated between the islands of Biak and Yapen, north of Cenderawasih Bay. The basin fill consists of three sequences with bounding unconformities traceable across the wider Bird’s Head region. These sequences form a complete megasequence that records changes in relative sea-level driven by uplift and subsidence within the region. The lowermost sequence comprises island arc volcanics accreted to the northern New Guinea margin at the end of the Paleogene. The top is marked by a Lower Miocene angular unconformity that can be traced to basins in the Bintuni region to the west. The middle megasequence within the basin is composed of Lower Miocene platform carbonates possibly correlative with the Kais Limestone found in the Salawati Basin to the west. The final sequence is marked by an unconformity caused by diachronous regional subsidence across the northern Bird’s Head that led to the drowning of localised carbonate platforms, including the collapse of the Kais Platform, and the initiation of strike-slip faulting. The movement along these faults has led to the formation of many of the modern sedimentary basins in the region.