What type of water does a drysuit keep out to provide thermal protection?

A drysuit is designed to keep all water out, regardless of its temperature or salinity, thereby providing thermal protection to the diver. The suit is fitted with seals and a waterproof zipper that prevent water from entering, which is essential for maintaining body heat. In colder diving environments, having a barrier against both fresh and saltwater is crucial for insulation and comfort during the dive. The construction of a drysuit allows divers to wear insulating layers underneath, which rely on the dry environment to keep them warm. This comprehensive water protection is what makes the drysuit an effective choice for cold water diving, versatile enough to handle different types of water conditions, including both freshwater and saltwater.