As Kath said it may be a good idea not to go swimming on the day your portacath is used for treatment. If you do swim I recommend you don't over do things and do gentle strokes. Your port is attached to your chest wall by three lots of sutures. There is a very small chance that if you are overly active the sutures could break. If the sutures break, there is a risk that the port can flip over. If it flips they will try to fix it by manual manipulation but if that fails you will require another surgery. I have broken my sutures twice now. The first time was 5 months after I had my port inserted. It flipped over and the manual manipulation failed resulting in a second surgery and anaesthetic. Then I broke my sutures again two weeks ago. Now my port is unattached and 'floating' in my chest but it hasn't flipped yet. The issue with my port is that it really isn't in the right place for my body type - it sits a little off-centre to my chest rather than up towards my shoulder like I see with other women. My large breasts end up pulling on the sutures when I am in certain positions. The nurses have still been able to use it while it has been floating but if it flips again I think I will have to have it removed as I can't keep having surgeries to fix it. Be reassured though they tell me my situation is very rare. My oncology nurse said that mine was the only flipped port he had seen in 15 yrs.
Best of luck with it
Nadine