This study confirms the existence of the blind cave shrimp Typhlocaris lethaea Parisi, 1920, in Lethe Cave, Benghazi, Libya, nearly a century after its initial discovery, and documents its new distribution in the Al-Coeffiah caves. Field surveys conducted in 2023 and 2024 revealed its presence in the El-Khadim and Al-Jebah caves, extending its known range by 9 km. Specimens were found in subterranean lakes characterized by complete darkness, with water parameters including an average temperature of 22 °C, pH of 7.67, and salinity of 4.72 ppt. Two specimens were used for further analysis. These findings suggest that the species is more widespread than previously thought and highlight the potential hydrological connections within the karstic system. Additionally, the discovery of a depigmented isopod in El-Khadim cave suggests further hidden biodiversity. Given its IUCN data-deficient status, our findings emphasize the need for conservation efforts to protect these fragile ecosystems from human impacts, ensuring the preservation of Libya’s unique subterranean biodiversity.