According to Genesis, Noah had three sons aboard the Ark: Shem, Ham, and Japheth. Genesis names the three sons before the Flood narrative and includes them among the people who entered the ark with Noah.
Genesis 7:13 lists Noah, his sons, Noah’s wife, and his sons’ wives as the human occupants of the ark. That makes eight people in total, though the question asks only for the number of Noah’s sons.
After the Flood, the three sons become central to the genealogical material in Genesis 10, often called the Table of Nations. The chapter traces peoples and territories through their descendants.
A frequent mistake is to count Noah’s wife or the three sons’ wives as additional sons. The text identifies those women separately. It also does not name Noah’s wife or the wives of Shem, Ham, and Japheth in the Genesis account, while the three sons themselves are explicitly named.