Background
The Costa das Algas Environmental Protection Area (EPA) and the Santa Cruz Wildlife Refuge (WR), located in the Espírito Santo Continental Shelf, Brazil, are outstanding marine protected areas due to their high biodiversity, particularly of macroalgae. Together, these two relatively small protected areas (1,150 and 177 km2, respectively) harbour about a quarter of all macroalgal species recorded in Brazil.The checklist presented herein updates the algal flora of these two protected areas with data obtained until 2019. Two hundred and sixty-five macroalgal taxa were recorded, most of which with vouchers. Checklists based on the collections of each protected area were published on: "Catálogo de Plantas das Unidades de Conservação do Brasil" (https://catalogo-ucs-brasil.jbrj.gov.br/). New information: Besides specimens collected between 2018 and 2019, the algal flora presented herein includes previous records from different Brazilian herbaria (e.g., SP, SPF, ALCB). Herbaria records may include species that do not occur in intertidal reefs (e.g., Laminaria). Overall, 249 macroalgal taxa and one marine angiosperm were recorded in the Costa das Algas EPA (87 new records) and 136 macroalgal taxa and one marine angiosperm in the Santa Cruz WR (46 new records). All taxa are native to Brazil and nine are endemic to Brazil. Our