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Haloarchaea are extreme halophilic microorganisms belonging to the domain Archaea, phylum Euryarchaeota, and are producers of interesting antioxidant carotenoid compounds. In this study, four new strains of <i>Haloarcula</i> sp., isolated from saline lakes of the Atacama Desert, are reported and studied by high-resolution mass spectrometry (UHPLC-Q-Orbitrap-MS/MS) for the first time. In addition, determination of the carotenoid pigment profile from the new strains of <i>Haloarcula</i> sp., plus two strains of <i>Halorubrum tebenquichense</i>, and their antioxidant activity by means of several methods is reported. The effect of biomass on cellular viability in skin cell lines was also evaluated by MTT assay. The cholinesterase inhibition capacity of six haloarchaea (<i>Haloarcula</i> sp. ALT-23; <i>Haloarcula</i> sp. TeSe-41; <i>Haloarcula</i> sp. TeSe-51; <i>Haloarcula</i> sp. Te Se-89 and <i>Halorubrum tebenquichense</i> strains TeSe-85 and Te Se-86) is also reported for the first time. AChE inhibition IC₅₀ was 2.96 ± 0.08 μg/mL and BuChE inhibition IC₅₀ was 2.39 ± 0.09 μg/mL for the most active strain, <i>Halorubrum tebenquichense</i> Te Se-85, respectively, which is more active in BuCHe than that of the standard galantamine. Docking calculation showed that carotenoids can exert their inhibitory activity fitting into the enzyme pocket by their halves, in the presence of cholinesterase dimers.