Waterproof B2 6.5mm Scuba Diving Boot

Waterproof 6.5mm B2 Boot: Cold-Water Dive Boot Built for Serious Insulation

The Waterproof 6.5mm B2 Boot is a thick neoprene diving boot designed for cold-water conditions where thinner boots simply stop doing their job.

If you regularly dive in cold or temperate water and come up with numb feet before the dive is done, this is the kind of boot worth looking at closely.

What 6.5mm Semi-Dry Neoprene Actually Means

Neoprene boots work by trapping a thin layer of water against your skin, which your body then warms. The thicker the neoprene, the better it holds that warmth and the slower it loses it to the surrounding water.

At 6.5mm, the B2 sits firmly in cold-water territory. This is not a travel boot or a warm-reef boot. It is built for the kind of diving where water temperature drops low enough that your feet are the first thing you feel.

The semi-dry construction means the boot is designed to limit water flushing through the interior. Cold water constantly cycling in and out strips heat fast. Reducing that flush is what keeps insulation effective over a full dive, not just the first few minutes.

Fit and Entry

The B2 uses a YKK zipper for closure. YKK is a well-regarded zipper manufacturer, and the choice matters here because a boot zipper takes repeated stress from pulling on and off over a wetsuit, often with cold, wet hands.

The zipper runs extra-long, which makes getting the boot on and off genuinely easier, especially when you are already suited up and working with limited dexterity in the cold.

The high-cut, angled shaft wraps up around the ankle. This gives you meaningful ankle support and helps seal the top of the boot against water entry. It also means the boot sits more securely under a wetsuit leg, reducing the chance of it riding down during the dive.

In the Water and Out

Reinforced rubber at the heel and toe extends the life of the boot in the areas that take the most punishment, both from finning and from walking on rocky entries or boat ladders.

The angled boot shaft is worth noting for anyone who has experienced calf fatigue or ankle strain on longer dives. The geometry is designed to reduce the stress your foot and ankle are under while kicking, which matters when you are wearing thick neoprene that already adds some resistance to movement.

The sole is described as durable and soft, with grip suited to slippery surfaces like boat decks and rocky shorelines. A boot this thick is not going to be your first choice for a long walk, but it should handle the practical business of getting in and out of the water without issue.

Who This Boot Is and Is Not For

The B2 is a cold-water specialist. If most of your diving happens in warm tropical water, 6.5mm will feel excessive and may make it harder to get your fins on correctly. A thinner boot would serve you better in those conditions.

If you dive in genuinely cold water, whether in northern lakes, temperate seas, or anywhere your wetsuit is already 7mm or a semi-dry suit, the B2 is built for exactly that environment. It is also suitable for kayaking and other cold-water watersports where foot insulation matters.

Pair it with fins that have an adjustable strap or an open heel, since a 6.5mm boot adds meaningful volume to your foot and will not fit comfortably into a closed-heel fin pocket sized for bare feet or thin booties.