Put about a quarter of a cup of baking soda inside large Ziploc (there's more great tips and useful tools when you go to their websites) bag when going to the beach.  Bear with me this gets really good.  Put your wet swimsuits in the bag and shake.  Place in 350 degree oven and bake ... wait a minute ... sorry wrong one.  Back to the beach.  The soda absorbs moisture and helps prevent mildew.  No more scary smells before you can get the suits laudered.  This is a great tip.  I wish I had known about this when my kids were younger.  But it's not too late for the rest of y'all.