Wetsuits need to fit snug to the body in order to insulate well. If you are rolling up sleeves and ankles, or the suit is sagging at the waist or hips, you are going to lose body heat in the water, basically negating one of the purposes of the garment. Related to the insulation function, this particular wetsuit is 2mm thick over the limbs and 3mm thick in the torso. Many other child suits here on Amazon only have 2mm thickness in the torso, so that is worth checking if it is of interest for your purposes.

In terms of fit, my very slim 6 1/2 - year old (weight = c. 43 pounds, build = long limbs and slender waist) fit perfectly in the size 6. I suspect that a child with a slightly larger build but similar height (not yet anywhere near 4 feet) might be able to get away with this suit due to the stretch factor, but there was not much room to spare at the inseam, so chafing might become a factor. In any case, when purchasing this suit, I would recommend watching the chart measurements very carefully rather than trying to gauge by a child's usual clothing size.

This is a back-zip suit, and the zipper leash is very long (perhaps 9 inches or so). My child instantly grasped the function of the leash and was able to zip the suit alone, but the Velcro that closes the collar is so strong that I had to open it myself (the angle plus child-level strength conspire against it). In other words, my child would be able to independently put on the dry, completely open suit except for adjusting the neck, but will need help getting it off.

The look and feel of this suit are substantial, and the closures move smoothly and function well. In other words, the suit does not 'read' cheap, which is very nice at this price point--but it does admittedly have a strong rubbery odor. That has been noted with different suits from this one by other reviewers, so I suspect it may kind of come with the territory. This suit will primarily be used in a pool, however, and so my child immediately decided that the chlorine simply had to kill the rubbery smell. We will see as soon as we are back at the pool later this week. I will revise my review after actually testing the suit in the water, if necessary, but for the time being we are very pleased.

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UPDATE: months on . . .

. . . the suit is _terrific_. Its wearer has grown (now 46 inches tall), but the fabric is soft enough with enough give that we are able to keep using the suit. We wash it after swimming in the pool (just in the washing machine) and air-dry it, and it is virtually unscathed despite being dragged over the concrete pool edge when climbing in and out. The color and decorations have held, the Velcro is still perfectly strong, and the leash and zipper are still in nearly as-new condition. There is some light fraying on the edges of the top around the collar and Velcro, but no one would probably notice that except me.

I would not call this a drawback, but it is worth knowing that there is really no getting this suit on and off the child without adult help. Part of it has to do with the snug fit, but part of it is that once it is wet it has to be turned inside out to get it off, limb by limb.

But we do not care, because this suit actually works to keep my child truly _warm_ at swimming lessons, even when the pool is notably colder than usual. I have had next to no remarks (let alone complaints) from my child about the pool temperature, and other parents are now asking where they can get one of these. (It helps that it is rather superhero-cool-looking, too.) I will not hesitate at all to buy the next size up when necessary, and I will probably still be able to sell the outgrown one, since it has stayed in such good shape despite its use.

This suit is light weight and fits true to size, My grandson loves it.

I tried this wetsuit and two others (Realon Shorty and Lemorecn Shorty). This is the best quality of the three.

The Aunua had nice stretch, good stitching, and a comfortable back closure. The closure at the back had velcro, but it was in the middle of a larger soft flap of neoprene. My child was comfortable.

The Lemorecn had just naked velcro at the back closure, with no protection against scratches or movement. Not sewn into anything.

The Realon was just way too big for the size it claimed to be. Huge on my kid.

We got three of these, one for each of our kids, for our vacation at the lake next week. Had them try it out in the pool today. After less than an hour of use, there is a hole at the seam at her torso. It wasn't too tight, it fit just fine, but then I saw the hole (about the size of a dime). I don't know if this will even last the week we need it for!
**UPDATED**
I wrote the above review contacted the seller (through the "contact seller" button) and ordered a replacement (I needed to do it right away to ensure that it arrived before we left on our trip). Before I went to bed that night, they had contacted me. They let me know that they saw that I had ordered a new one and that they would refund the cost of it for me. They were prompt and courteous. Good customer service - and my girls had a great time on the lake and didn't freeze!

Helped my grandson keep sand out of his bathing suit