I want to offer one set of thoughts more practically applicable to the question of just what modesty means, including as it relates to swimming.
Following on what I said in my previous post about not going to the extreme of prudishness, I would suggest - while certainly not going to an extreme - leaning toward the side of “covering up” more. The reason for this is simple: our lives are not about us, but about others. They are about sacrificing for the good of others. So, while we may want to wear a particular swimsuit, and while it may be perfectly morally acceptable to do so, that swimsuit may be too much for a weak brother of ours. Thusly, I would suggest figuring out, through prayer and good counsel, what is a good choice, and then taking some step down from that, as a small sacrifice of love for our brothers.
Secondly, I would really like to comment on one particular criticism of Fr. Joe’s piece pertaining to the susceptability of young men. One poster said he was essentially saying that “boys will be boys,” and that whie the boys have no responsibility for their own lusts, women ought to be wholly responsible for avoiding exciting them. Now as I pointed out, the post was written, in his words, “tongue-in-cheek,” but even apart from that i didn’t read what he said to say anything of the sort. Rather, as I read it, he was simply making a point which in my experience needs to be made over and over, which is that often times women really do not understand just how susceptible to movements of the flesh men, especially young men, can be. I have time after time spoken to women or girls who don’t grasp just how strong the male sex-drive can be. This is
no excuse for them not to fight their own spiritual battles and control their own selves. It
is a very important admonition that for most women, however easily excited a young man can be, the reality is far moreso.
For example, I was once visiting a (very modest) friend from college who was running a retreat for some high-school aged Catholics. One of the older women who was there had told the high-school girls not to hang around in the general social area in their pajamas (we are talking here about the way many or most high school girls dress these days for sleep: flannel style pants and a t-shirt) because it could get the boys excited. The girls thought this was silly, and the woman said they didn’t understand how excitable young men were. My friend agreed with the girls. The reality is, having been a young man, that that sort of attire
could easily excite some of those boys, even the most devout of them.
That is how susceptible the young male can be - of course not all of them, but certainly a fair share. It’s no excuse for them, but there’s also certainly lacking in charity to tempt someone in this way, however much of a fight against that temptation they will put up. It would be like drinking a beer in front of an alcoholic: there may be nothing intrinsically wrong with the act itself, but doing so in his presence can present un unecessary temptation. Depending on what you know of the alcoholic, it may be obligatory to avoid alcohol when he is around, and depending on what one knows of a given male, it may be obligatory to be “more modest” around him. Because we can not know about every person we will encounter at the beach or in public, charity dictates we take more caution with regards to modesty as we may deem objectively necessary.
This doesn’t mean women need to cover everything up!

I would simply say to be a little “more modest” than would may seem to be objectively necessary, and yet to do it within reason. In other words, you don’t need to go crazy… just take some one “extra step” that is
within reason to be appropriately modest.
Personally, in visiting some of the sites from the comments on Fr. Joe’s blog, I really like this one:
modestkini.com/?m=detay&urun=90 or this one:
modestkini.com/?m=detay&urun=150 I think that they both have a very nice balance between covering up what may be a difficult temptation for others, while not rejecting or hiding the human form that is such a wonderful and beautiful creation of the Lord’s. As a 25 year old man, when I look at the woman in those pictures, I am moved to a sincere appreciation and awe of her beauty, and I see her as a whole and beautiful person deserving of my attention, love, and respect. I’m not drawn to lust after or to objectify her, but I’m not moved to ignore or to fail to notice or to reject her body either (as I am in, for example
modestkini.com/?m=detay&urun=54)). Rather, when I look at those pictures I see the beauty of her body as integral to the beauty of her whole person; I see a person who’s beauty makes me want to get to know her better, but only as a particular facet of an entire human person. So I imagine that many may think that these suits are “too covering,” and I can understand that. At the same time, I think the most important thing I’ve had to say in all of this is how those images make me feel and how they move me as a young man. After all, all of the theory and theology and philosophy we put into this sort of a question is really geared toward one thing: fostering the most authentically Christian lives possible. At least for me, those images have affected in my soul a most authentically Christian reaction.
God bless!