Diego Ramírez de Arellano, Spanish sailor and cosmographer (b. c. 1580)
Diego Ramírez de Arellano (c. 1580 – 27 May 1624) was a Spanish sailor and cosmographer.

He achieved fame for piloting the Garcia de Nodal expedition to the region of the Strait of Magellan. The expedition discovered the Diego Ramírez Islands, the most southerly point visited by Europeans until the discovery of the South Sandwich Islands by Captain James Cook in 1775.