Swimming Apparel Advantage
You should be significantly faster. At least for me its a severial percentage point difference in time (something like 3%) when i go from wearing a drag suit to not, and that dosn't have nearly the drag that boarshorts would. Im gonna go ahead and guess something like a 5-10% improvement in time.
Honestly, you really shouldn't be training in board shorts anyway. Drag is good, it makes you stronger, but too much ruins your stroke. If you're training while compensating for board shorts, you'll race the same way, which is going to be inefficient. You can usually find closeout speedos and drag suits online pretty cheaply. Grab bag speedos are only $15, and you can probably find similar deals at other sites.
http://www.srsport.com/product_info.php/cPath/21_37/products_id/1355
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-Matt
Not fast enough.
And if you are too modest for real swim wear (get over it) or just want a little drag- I use cheap running shorts from Sports Authority. They've held up well so far. $15 a pair.
Life is short. Play hard and get dirty doing it.



I always swim in my board shorts (swim trunks) because I do not want to ruin my expensive triathlon shorts or buy swimming apparel. I also have a pool sprint coming up, and I have sent in my 100/m expected pace (based on my times while wearing my baggy shorts). The problem is that I might not be able to get back in the pool before the race and I am wondering how much faster I will be in tri shorts vs. long baggy shorts when I swim in the pool????