This is too big for my 5-year old son. The TYRs we have in the same size fit him better. Maybe he'll be able to wear them in a few years.

Arena has done a great job with this suit.  The suit uses a high quality polyester similar to that used in suits made for the European market.  So, you get the long-term durability of a polyester suit with the comfort of a nylon/lycra suit.  Arena made a similar suit for the American market back in 2000.  I got about 2 years of use out of it.  I'm hoping for the same here.  The suit is true to size, and may even run a bit large.  I wear a 30" waist in pants/jeans, and found that the 28" Arena suit fits perfectly.  There's a lot of overlap in waist sizes between the Adult and Youth makes of this suit.  I see only one difference.  The Adult suit is cut a bit more generously on the sides (2.75 vs 2).