Wendy,
When people refer to the underwater walking I believe they are talking about the "Aqua Safari" offered on Bora Bora. You wear your swimsuit (and I expect also your aqua shoes) and a yellow diving helmet is placed on your head just as you enter the water. Your head remains dry and you can even wear your glasses. The brochure says you remain just under the surface. The activity is suitable for most, but those with heart problems or who are pregnant many not participate.
