This study has depicted a scenario on assessing spatial and temporal land use/cover changes in and adjacent to marine protected areas (MPA) in a study site in Thailand. The measurement of landscape stability and its implications for protection and conservation of coastal resources are emphasized in this study. The methods employed include interpretation and analysis of satellite images, aerial photographs, and geographic information system (GIS) data. Image analysis and GIS techniques have been used extensively, and a site-specific geospatial database was developed accordingly. Initial temporal changes inside and outside protected areas are captured from visual interpretation of three time series satellite images, where an increase of aquaculture ponds and abandoned areas is clearly visible. The output changes derived from the image differencing techniques demonstrated considerable changes in the whole study area as well as inside the protected area boundary during 1976 to 1990. Compared to the earlier time (1976–1990) the changes during 1990 to 2005 are found to be less extensive. Although the existing marine protected areas were declared earlier than the 1990s, the changes are still found inside the protected area boundary during 1990–2005. The result shows significant increases in agriculture areas, including aquaculture development, which are, however, less inside the protected areas than the buffer areas. While mangrove areas have noticeable negative changes, an increase in Malalueca forest areas is interesting. In the discussion, a quantitative comparison of legislative boundary and buffer effects on protecting land use and land cover is illustrated. In light of existing ecological context and socioeconomic activities, observations are made on agents of change and resource use conflicts.