This is a tricky question because they are so many variables in roasting the meat (like oven temperature, how much the turkey weighs, how cold the turkey is, etc). For boneless skin-on turkey breast, 4-5 pounds, that is fully thawed, it takes between 1 ½ to 2 hours while baking at 350˚F. The most important is the internal temperature should reach at least 165˚F (though I prefer 170-175˚F).