Find somewhat modest swimsuits (made for muslims) by googling "burqini". I would post a link but links don't work for me in the anonymous forum.

Regular swinsuits are not modest enough to wear in public.

What about the other people there? How do you avert your eyes from every single other person in the public area?

 :dancing-banana:The answer, I think, is a great, "It depends......"
Who are you?  Your state in life?  Any children?  Teens/young adults?  Know your personal weaknesses?
Who will be in the public place?  Are there rules regarding modesty and behavior?  Are they enforced?  What is the goal of your swimming?  To cool off, exercise, enjoy nature?  Or to see and be seen?

I do swim in public under certain very limited circuмstances.  I am an older single woman, not interested or tempted by the presence of men, provided they are wearing, shall we say, minimum of shorts, T-shirt when visible. Swimming is one of the few forms of exercise I can do without making my arthritis worse.   Any beach or pool that is a "pick-up place" is automatically excluded.  While not tempted by others, I find the environment of such places repulsive.  There's no reason to go there.  
Okay, where would I swim?  Try an ocean, lake, river that is not crowded, eg. a national park or seashore, in a lake or river in a state forest preserve where there are few people, and if people are present, those who keep reasonably covered up.  A few favorites come to mind.  Moosehead Lake above Greenville, ME, Lake Richmond, Morgan Preserve, Fitzwilliam, NH, Long Island Sound between public beaches, especially when a boat is available to first get a ways offshore.  It's like having a private beach!  The brook at Elizabeth Furnace Forest, VA.  Last summer, I made myself an old-fashioned "swimming hole" by building a rock wall damn.  Macedonia Brook near Kent, CT.  There are certain campsites with private access to the water.  The Atlantic Ocean off of Brooklyn and Queens.  Go LATE in the season when the water is warm and the crowds gone.  (Technically illegal, since I go outside of lifeguarded areas.) Beaver Lake, Lake St. Francis, the northern "Chain" Lakes in the Adirondack Park, NY, wilderness areas.  If you really want to swim, places open to the public can be found.  Do not expect bathhouses, refreshment stalls, lifeguards, easy access.  But they do exist!  One of my favorite summer activities is to be floating in a natural body of water, surrounded by God's creation as the sun sets.  Beautiful!

A person could always wear long shorts and t-shirt.  I would recommend NOT dressing as a muslim under any circuмstances.

Marsha

Wear the speedo instead of the thong- problem solved.

This thread is a joke, right ?

What about the other people there? How do you avert your eyes from every single other person in the public area?

I don't go to such places.

Who convinced you you have to experience such places? Do you have a TV, and/or do you watch regular Hollywood movies? You've been programmed. I'm serious.

We're not here to have fun, we're here to save our souls. You're either serious about that goal or you're not.

You won't die if you never go to the beach. Trust me on that one (personal experience).

i would like to add, that it doesn't take public beaches to "have fun" either. There are plenty of ways to have fun that don't involve occasions of sin.

 
If I won the lotto I definitely would set up a  top of the range Catholic campsite with swimming pools for either sexes for modesty.  TLM masses with places of meditation in different parts of the campsite (ideally built into a wooded site) with daily public Rosary in a central gathering area.  A central community area for everyone to mix and hopefully a lot of marraiges could come out of this too.

Have to win it first :)

'Dat you, Crossbro?