TAMMY M This can be completely immersed in water with no fear of insides getting wet....as long as you roll over the top 3 or 4 times (sometimes I have been known to overpack it and only roll it once or twice and disaster occurs. I have been using this for ultramarathons (in which bags can get very wet very quickly in a storm or the storage area's can flood) and I have had no issues and highly recommend the bag!

TODD S Never tried it but it seems to have a good water-tight seal