Why do some people have veins visible in their boobs?

Normal: There is amble blood supply to the breast tissue, frequently there are veins that are quite prominent and clearly visible in the breast - that is normal. However a sudden change or a dramatic increase in the appearance of the veins of the breast should warrant an exam by your physician.

Normal finding: I am amazed about how often I have women ask me about the veins on their breast. Occasionally they are spider veins but mostly they are blue veins. These are almost always normal findings and normal variations of chest veins. They tend to be more pronounced in fair skinned females and they may be related to hereditary factors or even pregnancies. No treatment is necessary unless for cosmetics.