Conference handbook, programme, abstracts, and list of talks and posters from the 2010 Marine Geological and Biological Habitat Mapping international symposium (GeoHab 2010), held in Wellington, New Zealand, 4-7 May 2010. GeoHab (Marine Geological and Biological Habitat Mapping) is an international association of marine scientists studying biophysical (i.e., geologic and oceanographic) indicators of benthic habitats and ecosystems as proxies for biological communities and species diversity. The main goals of GeoHab scientists are: to support government spatial marine planning, sustainable ocean management, and decision making; to support and underpin the design of marine protected areas (MPAs); to conduct scientific research programs aimed at generating knowledge of benthic ecosystems and seafloor geology; to conduct living and non-living seabed resource assessments for economic and management purposes, including the design of fishing reserves. The theme for GeoHab 2010 is "Characterisation, Quantification and Divesity of Extreme Habitats". The conferecne proceedings comprises the complete abstracts submitted for the conference, listed in alphabetical order by first author.