Swimsuits

I initially found them on-line, but our local Kohl's had them in stock as well, so you might want to check out your Kohl's first and order if they don't have it. 

What's great about the tankinis is I can get by with a black skirted bottom, and get different tops so I have a variety of suits.  The tops work out to about $24 on sale, so you can get the equivalent of 2 to 3 suits for what one mast suit would cost.

vhshea

They work well for a mast because they cover the chest almost to the neck.  Most suits are cut too low for me, though they might work ok for others.  If I lean forward, they gap out and you can see down my suit top.  If you need to wear some sort of prosthetic, you can either sew a pocket in the suit, or just pin a foam form into it. 

Your best bet would be to just try on some suits and see what works.  Until your exchange surgery, you probably want a suit that won't reveal the uneveness until your exchange.  Plus, it depends upon how your scarring is, and if it will show in some suits.  Probably a deep V isn't going to work too well at this point for you.  The tops I posted links to are good for hiding what you don't want people to see, but still very cute and fashionable.  I'm not a bikini type either - 58 is just a little bit too old to be flashing that much skin - especially at my weight!  I definitely do not want to show off my lovely chemo belly!

If I was a double mast, I would be able to wear more swimsuits, but with a single mast, you can tell the difference.  Even though I'm only an A, you can tell how much tissue was removed up to my breastbone, and a suit has to come fairly high to hide that.  Otherwise I could wear a bandeau top with no problem.  I have a port as well, but I don't worry about trying to hide it, as it's not really that obvious.  I don't care if they can see the scar, as it's not all that large.