This study provides the first records of the upside-down jellyfish Cassiopea andromeda (Forskål, 1775) in the eastern Atlantic supported by molecular analysis. Specimens were observed, recorded, and sampled in an inland aquaculture facility in September 2023 in Tenerife Island (Canary Islands). This new record officially demonstrates the geographical expansion of C. andromeda, and the introduction of a new potential invasive species in the Macaronesia oceanic island system.