A turning insert comprising a top surface, an opposite bottom surface, side surfaces connecting the top surface and the bottom surface, a reference plane located parallel to and between the top surface and the bottom surface, a center axis extending perpendicular to the reference plane and intersecting the reference plane, three nose portions (15, 15', 15") formed symmetrically around the center axis, each nose portion (15, 15', 15") comprising a first cutting edge (11, 11', 11"), a second cutting edge (12, 12', 12") and a convex nose cutting edge (10, 10', 10") connecting the first (11, 11', 11") and second (12, 12', 12") cutting edges, wherein in a top view the first and second cutting edges on the same nose portion forms a nose angle (α) of 25-50° relative to each other, wherein the bottom surface comprises rotation prevention means (40, 40', 40", 41, 42, 43, 44), wherein bisectors extend equidistantly from each pair of first (11, 11', 11") and second (12, 12', 12") cutting edges and wherein each bisector intersects the center axis, and wherein the first and second cutting edges (11, 12) are symmetrical or substantially symmetrical relative to the bisector in respective side views, characterised in that the first cutting edge comprises a first sub-portion and a second sub-portion, wherein a distance from the nose cutting edge to the first sub-portion is shorter than a distance from the nose cutting edge to the second sub-portion, wherein a distance from the first sub-portion to the reference plane decreases at increasing distance from the nose cutting edge, wherein a distance from the second sub-portion to the reference plane increases at increasing distance from the nose cutting edge. a top surface, an opposite bottom surface, side surfaces connecting the top surface and the bottom surface, a reference plane located parallel to and between the top surface and the bottom surface, a center axis extending perpendicular to the reference plane and intersecting the reference plane, three nose portions (15, 15', 15") formed symmetrically around the center axis, each nose portion (15, 15', 15") comprising a first cutting edge (11, 11', 11"), a second cutting edge (12, 12', 12") and a convex nose cutting edge (10, 10', 10") connecting the first (11, 11', 11") and second (12, 12', 12") cutting edges, wherein in a top view the first and second cutting edges on the same nose portion forms a nose angle (α) of 25-50° relative to each other, wherein the bottom surface comprises rotation prevention means (40, 40', 40", 41, 42, 43, 44), wherein bisectors extend equidistantly from each pair of first (11, 11', 11") and second (12, 12', 12") cutting edges and wherein each bisector intersects the center axis, and wherein the first and second cutting edges (11, 12) are symmetrical or substantially symmetrical relative to the bisector in respective side views, characterised in that the first cutting edge comprises a first sub-portion and a second sub-portion, wherein a distance from the nose cutting edge to the first sub-portion is shorter than a distance from the nose cutting edge to the second sub-portion, wherein a distance from the first sub-portion to the reference plane decreases at increasing distance from the nose cutting edge, wherein a distance from the second sub-portion to the reference plane increases at increasing distance from the nose cutting edge.