ABSTRACT The Tamar gas field, discovered in 2009 by Noble Energy, Delek, and partners, paved the way for a series of presalt discoveries that expanded our understanding of the petroleum systems in the east Mediterranean and the region’s hydrocarbon prospectivity. Approximately 40 tcf of natural gas has been discovered in the Oligocene–Miocene so-called Tamar sands play offshore Israel and Cyprus, which includes some of the largest deep-sea gas discoveries in the world over the last decade. The Tamar field development was expedited such that first gas occurred by March 2013, a mere 51 months following drilling of the wildcat well. Deep-water presalt exploration offshore Israel began in 2003 with the Hannah-1 dry hole. Following a 5-year hiatus, a new subsalt exploration and drilling program began in earnest in 2008, resulting in gas discoveries at Tamar, Dalit, Leviathan, Dolphin, Tanin, Aphrodite, Karish, and Tamar Southwest. The main presalt play area likely extends nearly 30,000 km 2 (11,583 mi 2 ) in water depths of approximately 1300 to 1700 m (4265 to 5577 ft), in the exclusive economic zones of Egypt, Israel, Cyprus, Lebanon, and Syria. The Tamar sands reservoir section is comprised of deep-sea floor fan sandstones punctuated by relatively thin beds of silts and mudstones. The accumulations are characterized by thick deposits, over 250 m (820 ft) of gross pay at Tamar, of high-quality reservoir with >20% porosity and >500 mD permeability. The lean gas (over 98% methane) is thought to be biogenic and sourced from the interbedded shaley units, whereas the seal is the regionally extensive early Miocene silty-shaley unit termed the Ng10 shale. Traps are faulted, four-way closures reaching over 100 km 2 (39 mi 2 ) at Tamar and approximately 330 km 2 (127 mi 2 ) at Leviathan, the largest discovery to date. Over 140 m (459 ft) of conventional core has been collected from one appraisal and two development wells at Tamar, and an extensive suite of side-wall cores were taken in the other wells. Core calibration has proven critical to petrophysical evaluation, resource assessment, and completion design. The Tamar field was developed in under 51 months from discovery to first gas for $3.25 billion in gross development capital. Current production at Tamar is accomplished from five subsea wells, each capable of producing over 250 MMSCF/day and tied back through a subsea manifold to a fixed-leg processing platform located some 150 km (93 mi) south of the field. At the time of development, this was the longest deep-sea tieback in the world. From there, the treated gas is flowed to an onshore terminal in the coastal city of Ashdod. Tamar is currently the only significant provider of natural gas to Israel and has supplied nearly 1.0 tcf of gas as of year end 2016, which fuels over 50% of the local market’s power generation needs. The discovery and development of Tamar opened a new chapter for the eastern Mediterranean oil and natural gas industry.