An airfoil includes an airfoil body that has a peripheral wall that defines an exterior side and an interior side that bounds an internal cavity in the airfoil body. The peripheral wall has first and second wall sections joined by a transition section. The first wall section is thicker than the second wall section. The transition section provides a change in thickness between the first wall section and the second wall section. The second wall section includes a cooling hole that has a first end that opens to the internal cavity at the interior side and a second end that opens to the exterior side.