What were the names of Isaac's twin sons?

Answer: Esau and Jacob

Rebekah gave birth to twins: Esau came out first, then Jacob, grasping Esau's heel.

“The first one came out red, covered with hair like a fur coat; so they named him Esau. After this, his brother came out grasping Esau’s heel; so he was named Jacob. And Isaac was sixty years old when the twins were born.”— Genesis 25:25-26 (BSB)