<p>In developing countries, regional spatial development often results in unintended consequences, such as rural-to-urban migration and the growth of informal settlements in cities, leading to social, economic, and spatial disparities. This study examines Chabahar, a city in Iran’s Sistan and Baluchestan Province, which has been affected by large-scale regional spatial development, resulting in the spread of informal settlements in its outskirts and associated negative impacts. To address spatial inequalities, particularly in the informal settlements near Chabahar, a systematic and phased development-oriented planning process is proposed as a solution to achieve sustainable development and efficient land management. Through the Delphi method, spatially balanced development criteria and indicators are assessed. Hierarchical analytical analysis, with support from EXPERT CHOICE software, prioritizes and weighs environmental compatibility indicators for integration into Geographic Information Systems (GIS) modeling. This research aims to offer a suitable framework for regional spatial development, focusing on informal settlements. The findings from Phase 1 Micro-Scale Intervention target housing shortages and formalizing informal settlements in Chabahar by utilizing underutilized areas and land reserves. The “First Popular Wave” involves the community in creating detailed local plans for systematic residential plot allocation. Phase 2 Macro-Scale Integration aims to transform the city on a citywide scale from 2023 to 2030, providing housing and services to meet current needs and achieve long-term development objectives. The objective is to integrate the study area into Chabahar’s urban framework, ending informal settlements through planned redevelopment to prove a sustainable urban environment that supports strategic development goals.</p><p><b>Clinical trial number</b> Not applicable.</p>