The conventional hydrothermal conversion of saccharide-based precursors typically leads to the preparation of regularly sized carbonaceous microspheres. However, these materials typically present very low surface areas and limited porosity. Therefore, if these sustainable carbons are to find use in applications where surface area, porosity, mass transfer and diffusion are critical to function then innovative routes are required to introduce high surface area and (e.g. micro-, meso- and macro-) porosity as well as allow material morphology control. In this chapter the use of the hydrothermal carbonisation (HTC) approach in the synthesis of porous carbonaceous materials will be discussed based on sustainable precursors. The use of hard (e.g. silica-based) and soft (e.g. micellar) templating techniques to dictate porosity and morphology will be discussed transiting through a variety of approaches including the use of inorganic nanoparticles/wires, block copolymers, and latex nanoparticles through to increasingly more sustainable and efficient approaches involving oil-in-water emulsions, low-density aerogels and ultimately the use of naturally forming structures (e.g. crustacean exoskeletons) to render these functional, sustainable carbonaceous materials with high surface areas and flexible porosity features coupled with the ability to dictate material morphology, in a fashion akin to classical sol-gel chemistry.