Oil and gas exploration in the Java Sea Basin extends back to the late 19th century. The onshore and near-shore sectors are well explored, and have an established network of production and transportation infrastructure. Recent exploration has predominantly targeted low-risk, near-field opportunities. The average discovery over the last decade has been modest and commercial finds have been rare. More remote parts of the basin remain under-explored and may offer more material volume potential. The mature onshore and shallow-shelf operating environment offers low-cost development opportunities. However, lead times vary and impurities in oil and gas can add to development costs. The cumbersome Indonesian regulatory system often slows progress towards development. Regulators have been actively reviewing the investment environment and fiscal elements, however measures introduced over recent years have not proved sufficient to boost activity.