Southeast Asia is replete with Cenozoic sedimentary coal-bearing basins. These basins can be grouped into five regions: northern Sundaland, southern Sundaland, the Philippine archipelago, western Myanmar and eastern Indonesia. Only the first three are discussed in this paper. Each of the three areas has unique coal basin properties as a result of differing tectonic, palaeogeographic, palaeoclimatic and depositional histories. The most significant coal deposits of SE Asia formed in large sedimentary basins within the Neogene in southern Sundaland (the islands of Borneo and Sumatra) over extensive coastal plains, in a regressive setting, and multiple seams of >5 m thickness are widespread. Locally much thicker seams have delveloped. Typically, the coal deposits have low ash yield and sulphur contents. In contrast the interior coal deposits of northern Sundaland formed within small disconnected grabens and half grabens, with continental fill, and were not influenced by marine base level changes. The coal deposits are areally restricted. Coal thickness is variable, with one or two main seams, up to 6 to 20 m when well developed, but there are locally much thicker coal-dominated stratigraphic intervals. The ash yields are usually moderate to high and sulphur contents are variable, often high. Coal within the basins of the Philippine archipelago typically has similar coal quality to the coal deposits of southern Sundaland with variable coal rank but the deposits are not extensive, being limited by basin size and structural complexity. Southern Sundaland has had the least change palaeogeographically, residing mainly within +/- 10 degrees of the equator. Its palaeoclimate has remained conducive to ever-wet conditions, the climate most favourable for peat formation, throughout the Cenozoic. Northern Sundaland (i.e. SE Asian continental) has consistently resided >10 degrees north of the equator throughout all of the Cenozoic. The palaeoclimate was therefore tropical but probably monsoonal with significant annual dry periods. These conditions are not the most conducive to peat formation. In contrast to the Sundaland basins, the Philippine archipelago had less tectonic stability and has a complex palaeogeographic history with some regions passing through equatorial areas (and climates) while others were always north of the equator. The tectonic and depositional histories of the three regions are unique and contributed to the character of the resultant coal. Basins in northern Sundaland were most affected by the collision of India with the Asian continent during the Palaeogene. Syn-rift basins formed within continental crust resulting in small, mainly disconnected basins which were filled with coarse but generally fining up sequences containing coal seams and sediments of freshwater lacustrine and fluvial origin. The basins did not develop beyond the syn-rift phase, being constrained by the intra-continental setting and probably the stresses from the India-Eurasia collision. The southern margin of Sundaland also was affected by Palaeogene extension resulting in the development of small syn-rift basins containing a similar initial sequence to northern Sundaland. However, after the initial rifting much larger wider basins formed. This probably reflects major differences in the fundamental crustal architecture and lithosphere between northern and southern Sundaland. The initial syn-rift (and early post-rift) rock units were eventually transgressed by marine sediments. Later basin inversion and mountain uplift in the hinterland provided a sediment source for the deposition of widespread fluvial-deltaic and coastal plain sediments. Areally extensive peat mires then formed, within a regressive sedimentary sequence. The tectonic development of the Philippine archipelago is extremely complex. The archipelago is composed of modern and ancient island arcs and merged continental fragments. Various rifting and amalgamation of micro continental fragments had resulted in a plethora of small coal-bearing basins most of which are dissected and structurally disturbed. Southern Sundaland (i.e. the islands of Sumatra and Borneo) has the most extensive coal deposits in SE Asia, During the Cenozoic the region had the right sequence of tectonic events, palaeogeography, and palaeoclimate. Laterally extensive coal seams developed during the Eocene in southeast and central Kalimantan (Borneo) in an early post-rift setting under conditions of relative marine transgression. By the Middle Miocene the basins of southern Sundaland were experiencing a depositional setting with palaeogeographic and palaeoclimatic conditions that were conducive for the development of widespread and thick ombrogenous peat mires, which resulted in the formation of vitrinite-rich coals with low ash yields and low sulphur contents. The combination of large basins that quickly infilled to base level, an ever-wet climate, and a depositional setting where peat mires could form and be preserved resulted in the formation of areally extensive and thick coal deposits from the Middle Miocene through to the Pliocene. Although there are locally significant coal deposits in northern Sundaland, the depositional setting was within small continental-fill syn-rift grabens, many with a lacustrine environment, in a seasonally drier palaeoclimate than southern Sundaland. Development of peat mires was not areally extensive, and the coal seams have higher ash yields and sulphur contents, and a locally higher content of liptinite macerals. Coal deposits in the Philippine archipelago developed under broadly similar palaeoclimates to southern Sundaland, with a similar range of coal qualities. However, the structural complexity and limited areal extent of many of the coal deposits reflects the tectonic complexity during and after the period of coal formation. (C) 2016 Elsevier B.V. All rights reserved.