Using local materials with low environmental impact is essential in building living spaces, combining energy efficiency, environmental respect, and user well-being. However, despite advances in using natural materials, few studies have focused on integrating spathe fibers into earth bricks to optimize their thermal, mechanical, and hydric performance. The study aims to develop an innovative approach to using spathe fibers as natural reinforcement in manufacturing soil bricks while analyzing their impact on thermal, mechanical, and hydric properties. Several soil bricks reinforced with spathe fibers at different concentrations (0%, 1%, 2%, 3%, 4%, and 5%) were developed. Thermal performance was assessed using the hot disk method, while mechanical strength was measured in compression and flexure with capillary absorption tests. Based on fiber content, the brick density ranged from 1719.75 to 1247.6 kg/m3. The thermal conductivity of the materials ranges from 0.621 to 0.327 W/m. K, indicating good insulating performance. Maximum capillary water absorption values range from 170 to 287%, revealing a difference in water permeability depending on fiber content. Compressive strengths range from 1.4 to 3.6 MPa, and flexural strengths range from 1.6 to 1.91 MPa, suggesting potential for structural applications. Physico-chemical and geotechnical analyses confirm the suitability of the soil for the production of spathe fiber-stabilized bricks. This study offers an alternative to conventional bricks, contributing to the promotion of ecological and sustainable building materials suitable for arid and semi-arid climates.