In Genesis, Noah’s oldest son listed first among his three sons is Shem.
Genesis 5:32 names Noah’s sons as Shem, Ham, and Japheth. The same order appears in Genesis 6:10, before the Flood narrative describes the family entering the Ark. Shem is therefore the first-named son in the biblical account.
Shem later receives a substantial genealogy in Genesis 10 and 11. Genesis 11 traces his descendants through Arpachshad to Abram, later called Abraham. Because of this genealogy, Shem occupies an important place in the biblical account of ancestry after the Flood.
The text does not explicitly say that Shem was Noah’s oldest son in every chronological sense; it lists him first, and translations and interpretations discuss the ages in Genesis 10:21. A safe identification from the Ark narrative is that Shem is the first-named of Noah’s three sons. Ham and Japheth are the other two sons, not alternative names for Shem.