Hoods

Thickness — match to water temperature and suit
A 2mm hood suits water in the 18°C to 24°C range where some head protection is wanted without significant bulk. A 3mm hood covers the 12°C to 18°C range and is the most popular choice for recreational cold-water diving in Canada's warmer seasons. A 5mm hood is used in water from 7°C to 12°C and for extended dives in temperate conditions. A 7mm hood is for the coldest Canadian diving — late fall, winter, and ice diving — where maximum thermal protection at the head is essential. Match the hood thickness to your wetsuit thickness: a 7mm wetsuit with a 2mm hood creates a thermal imbalance where the head becomes the primary point of heat loss.

Standard hood vs. bib hood
A standard hood fits over the head and seals at the neck, more commonly used with a drysuit. A bib hood extends down over the neck and shoulders, tucking under the wetsuit collar to create a continuous seal between the hood and the suit — eliminating the gap where cold water flushes in at the neck. For cold water diving, a bib hood is significantly warmer than a standard hood used with a separate wetsuit collar. The bib tucks inside the wetsuit collar at the back and sits over the collar at the front. If you dive regularly in cold Canadian water and are still losing warmth at the neck and shoulders, switching from a standard to a bib hood is one of the most impactful single changes you can make.

Fit — snug at the face opening
A diving hood should fit snugly around the face opening — at the chin, cheeks, and forehead — without excessive pressure on any one area. The face opening should be close enough that minimal water enters during the dive but not so tight that it restricts circulation to the face or causes pain at the temples over a long dive. Hoods that are too large allow significant water flushing every time you turn your head. Some hoods include a built-in face seal or chin strap to improve the seal around the face opening. When trying on a hood, move your head side to side and look up and down — the hood should move with your head rather than staying behind.

Ear squeeze and hood use
Some divers experience ear discomfort when using a hood because the sealed air space over the ear can create a pressure differential from the surrounding water. Most diving hoods include a small drainage hole or a thinned area over the ear to minimize this effect. If you experience ear discomfort while using a hood, ensure the hood has a drainage hole aligned with your ear canal, or try a hood specifically designed with an open ear design. A hood should never be so tightly sealed over the ears that water pressure cannot equalize through the small drainage opening during descent.