We provide the first inventory of terrestrial arthropods from La Chimba National Reserve (Antofagasta Region, Chile), a protected area whose purpose is to preserve the biota of the Coastal desert of Tocopilla embedded in the larger transitional coastal desert. The study was conducted during spring of 2019. A total of 2,852 specimens were recorded, distributed across 188 species. Among the collected specimens, 5 new species were identified: two species of scorpions, Brachistosternus chimba Ojanguren-Affilastro, Alfaro & Pizarro-Araya, 2021 and Rumikiru sp. nov. (Scorpiones: Bothriuridae); a solpugid (Solifugae: Ammotrechidae); a spider (Araneae: Filistatidae), and a centipede (Scutigeromorpha: Scutigeridae). The richness estimations showed large values for most arthropod groups, which is evidence of an incomplete inventory of species richness. The article also discusses the current threats faced by these communities of endemic arthropods and suggests immediate actions to preserve these groups in extremely fragile semiarid ecosystems.