Anecdotal evidence points to an overall loss of coastal natural character in New Zealand since preserving the natural character of the coastal environment first became a statutory policy-goal in 1973. Today the preservation of the natural character of the coastal environment is one of the matters of national importance in the Resource Management Act 1991 (development control legislation) and one of the purposes of the Reserves Act 1977 (protected area legislation). There has, however, been no quantitative measurement or systematic monitoring of changes in overall natural character. The purpose of this thesis has been to develop a robust quantitative methodology for measuring natural character and its change using a consistent framework across terrestrial, freshwater and marine coastal environments. While methodology development took place in Northland, New Zealand, the methodology has been designed to be applied throughout New Zealand. With modification it would also have applicability in other countries. A comprehensive definition of natural character was developed for the New Zealand environmental, legal and policy contexts that also addressed the role of perception. Court decisions on appeals lodged under the Resource Management Act were found to be generally consistent with this definition. The Quantitative Index for measuring the Natural Character of the Coastal Environment (QINCCE) methodology was developed using indicators (and environment-specific parameters) derived from the comprehensive definition of natural character. A consistent framework is used for measuring natural character across terrestrial, freshwater and marine coastal environments. The methodology can be applied at a range of scales and for a range of purposes. For each broad class of coastal environment there is a core set of parameters that are used to calculate three sub-indices for each plan-view unit: • An ecological naturalness index (ENI) • A hydrological and geomorphological naturalness index (HGNI) • A freedom from buildings and structures index (FBSI) These three sub-indices are combined to give an overall natural character index (NCI) for each unit, which can be multiplied by 100 to give a natural character score between 0 and 100. Second tier parameters and alternative measurement perspectives have been developed for those situations where additional detail is required. Several key parameters are measured relative to the reference condition present-potential natural state. One is Score representing progress towards present-potential cover where present-potential cover is the terrestrial and aquatic land cover that would be present today had natural processes proceeded without the arrival of humans, the species they introduced and the consequential changes to the environment. Scoring tables for measuring progress towards present-potential cover have been developed for eastern Northland. Hydrological and geomorphological naturalness is assessed relative to the equivalent present-potential natural state. Protocols for addressing interactions between the hydrological and geomorphological, and cover parameters have been developed. This includes distinguishing between natural versus human-induced, and on-site versus off-site sources of disturbance. As part of the methodology refinement process, 113 “informed” participants scored their perceptions of natural character for 40 coastal environment photographs. These perceived scores were compared with scores calculated for the same photographs using the QINCCE methodology applied using an oblique Viewpoint perspective. The results assisted with the subsequent refinement of the scoring protocols for some parameters, and the construction and combination of the QINCCE indices.