Coastal peatlands are dynamic systems, part of the complex interplay of shallow marine and fluvial depositional environments, and are responsible for significant accumulation of plant matter. Low sulfur and low ash peats forming in close proximity to marine influence and active clastic depositional environments is a seemingly enigmatic occurrence. However, the rock record reveals these types of coals have occurred throughout geologic time. Here we share two examples of preserved coastal peatlands from the Late Cretaceous in USA, and the Paleocene in Australia.