they are pretty good. the sound gets a little muffled while you are swimming but you can fix that with some ear wax. The ear phones are pretty large and they make your ears sore if swimming for more than 30 min.

like the other reviews, they wouldn't fit in my ears.  I ended up getting the pioneer "splash proof" headphones instead. Works just as well and they stay in my ear

Despite all my efforts these would not fit snugly in my ears. I don't have a huge head, so think it's simply poor design. I am sending them back. If you purchase a pair, please keep all packaging in case they don't work out for you.

I use these with an Otter box and 1st Gen iPod Shuffle (512Mb).  It's a bit awkward to put on and the ear pieces need to be aligned correctly.  I use it with a Finis snorkel when swimming, and keeping your head submerged and steady makes for pretty good sound quality.  I really like the spring coiled cord that stays out of my way - I use it with my mp3 player under an arm band or tucked under my suit's waistband at the small of my back.  I've used another waterproof ear plug set, but they often get knocked out during flip turns or sprint speeds.  I wish there was a bone conducting headphone set like the Finis SwiMP3v2 that didn't force you to buy the integrated mp3 player...

I'm buying again only because I can't find anything that has worked any better.  I had great sound, however the cord kept shorting out which was extremely annoying.  When it did work, it made swimming absolutely incredible, so I'm back even if I get to use them only for another 4 to 6 mo. before it shorts out the music was worth it.

I've been using it while I swim for a little over a month and am not impressed with the headphones. Dont get me wrong, it looks really cool and was somewhat uncomfortable at first but I got used to it.

Problem is that water somehow still manages to get in your ear and you have muffled sound. I think it would be great if you were in a kayak or sitting by the pool with kids splashing in the water but its not great for swimming. Sound quality isnt that great either.

So if youre looking for great audio and constant sound while your swimming, I wouldnt recommend it.