swimming doesn't build muscle, not now, not ever
Might not give you massive muscles, but then what do you need massive muscles for, unless you're lifting heavy stuff all the time for a living?
Swimming is a brilliant form of exercise. And it does help to strengthen and condition certain upper body muscle groups. Plenty of swimming can lead to a lean, toned well buff physique like mine.
Swimming, running, cycling and stuff like press-ups, sit ups and a few weights is all you need to achieve buffness. Bulking up just slows you down and ends up as fayt if you don't keep exercising. Stay slim, it's healthier. Body builder types can suffer from all sorts of health problems, like high blood pressure and joint problems and that from over exerting the body beyond it's reasonable natural limits. Best to just stay the same sort of body type, but just tone up and be fit.
Plenty of bulky blokes down my local gym, but most of 'em can't do much with all that bulk. Utter waste of time, all that if you ask me.