Sea turtle sex is temperature-dependent, with pivotal temperatures (~28.7–29.3 °C) stabilizing sex ratios. We introduce a modular incubation box for in-situ nest protection on Cabo Verde’s commercial beaches. The design integrates passive shading, airflow enhancement, predator deterrence, and solar-powered sensing/ventilation to guide nest temperatures toward the pivotal range during the thermosensitive period. A community-friendly, easy-to-assemble kit is also included.