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January 20, 2017
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May 10, 2017

65 Diving Semi-Dry Wetsuit

(2 customer reviews)


Sticking to our beliefs in what we know about neoprene and diving suits in general, we have made clever use of modern technical fabrics and the latest technology in seal skin finishes to make this semi dry the best we’ve ever made.

Unisex fit.

Will Goodman put the previous version of our 6 x 5 Semi-Dry  to good use achieving a world record CCR dive in 2014, this model is even better.

Following a years training Will descended to a record depth of 290m, although because all the gauges stopped at this depth, it is believed that he actually achieved over 300m.

This suit can be worn from early summer through to mid September here in the UK
(14°c – 18°c) and comes into its own in the winter Red Sea and the Mediterranean.

By adding the O’Three Deep Skin Short John, this temperature range can be increased.

SKU: 65semidry Category:


  • The Neoprene: The most critical element of any suit. The neoprene we use gives a high degree of comfort and flexibility, whilst minimising compression, maximising its recovery, therefore keeping you warmer for longer. O’Three’s 65 Semi Dry uses three densities of quality dive grade neoprene.

  • The Fabrics: In order to capitalise on the quality of the neoprene, we need to laminate it with the best fabric combinations. From the durable 210D fabric used on the seat and front of the legs, to the Thermal Plush used internally throughout the Torso, no fewer than 8 different linings have been utilised, each having a specific function and job to do.

  • The Cut: Tailoring and ergonomically shaping remain a priority. Get it right and the detail in marrying the Neoprene and Fabric combinations will come into their own.

  • Thickness: 6mm Body, 5mm Arms and legs.

  • Thermal Plush: Internally the torso has been laminated with Thermal Plush. This new material combines fibres and a unique weaving technique that will increase warmth and speed up drying times.

  • Seams: Triple glued and blind stitched, resulting in watertight seams.

  • Stretch Panels: A careful combination of supply neoprene and ultra-stretch linings, tailored into areas that require additional flex and comfort.

  • 210D – Fabric: A tried and tested version of the material we use on our Ri2-100 Dry Suit. 210D has been used on the rear and front leg panels.

  • Sea seal: Pressure fit glide skin wrist seal.

  • Floating Collar: A soft micro mesh combined with a super ultra-stretch lining resulting in a neck seal that floats and contours your neck like no other. Adjustable Velcro closure.

    Modern fabrics have allowed all manufacturers to produce products that now stretch and flex like never before.  Velcro will attach to some of these fabrics, this small disadvantage is far outweighed by the advantages of these modern fabrics. The issue is easily avoided by always marrying both parts of the Velcro when not in use.

  • Zip: YKK HD metal slider back zip.

  • Knee Pads: 210D Fabric has been reinforced with a strong, yet flexible PU laminate.

  • Storm Guard: 1mm super ultra-stretch neoprene barrier subtly incorporated into the zip panel, creating a 100% waterproof guard.

  • Colour choice: All Black, with Alloy Blue and Mid Blue graphics Black with Pewter Grey Torso, with Orange / Silver Grey graphics.

We only use dive grade neoprene – no compromise.

Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in a fruit salad.

Squeeze a ripe tomato and what do you get.  This same logic applies to neoprene.


Soft = Compression = Collapse = Cold

Before buying your Semi Dry, feel it, squeeze it, stretch it.
If it feels like a piece of elastic, lacks density and guts, it will let you down in more ways than one.


Dive / Surface Neoprene – The difference and why you should be concerned.

Please take a little time to read and think about what is explained below, before you buy a wet / semi dry suit for diving.

Neoprene was invented by DuPont in 1930 and remains the best thermal insulator for any water sport, above or below the surface. As you would expect, neoprene has evolved in those 85 years. Refined techniques and huge investment has created a range of Neoprene suitable for applications from Running Tracks to Triathlon Wetsuits.

The vast majority of people who enjoy water-sports and wear a wetsuit remain at the surface.

The demand for extreme flexibility and movement has been and remains the overriding factor for the surf and surface water sports industry.  It is this sector that has been driving that neoprene evolution.

We have neoprene available today which has been specifically developed to be super light and ultra-soft, which is then laminated with ultra-stretch super extend materials, that has quite simply surpassed what any of us in the industry thought could have been achieved only 8 to 10 years ago.

However, it is only diving that inflicts a sustained compression on your neoprene product.

It is the thickness of the neoprene that is your insulator.   The softer the neoprene, the thinner it will become at depth.   A really soft 5mm suit will be half its thickness at just 2 meters (6feet).   At 30 meters it’ll be paper thin.

Softer neoprene will allow over stretching, creating thin spots even before you get under water.

Softer neoprene will not recover from compression.

The longer and deeper your dives, the quicker this will happen.

O’Three use several types of neoprene.  The vast majority of which have been developed specifically for diving.  These neoprenes have more mass and strength, whilst remaining flexible and comfortable.

It may take a little longer to don and doff and therefore to sell an O’Three semi dry, but we will not compromise the diving grade materials we use.  Ultimately, it is these materials that are helping to keep you warm and in the most extreme circumstances alive.

Size Guide

Unisex Size Guide

Small5’4" - 5’6"
162 - 167cm
34" - 36"
86 - 91cm
27" - 29"
69 - 74cm
32" - 34"
81 - 86cm
Medium5’8" - 5’10"
172 - 177cm
38" - 40"
97 - 101cm
31" - 33"
79 - 84cm
36" - 38"
91 - 97cm
Medium Tall5’10" - 6’0"
177 - 182cm
38" - 40"
97 - 101cm
31" - 33"
79 - 84cm
36" - 38"
91 - 97cm
Medium Large5’10" - 6’0"
177 - 182cm
40" - 42"
101 - 107cm
33" - 35"
84 - 89cm
38" - 40"
97 - 101cm
Large6’0" - 6’2"
182 - 187cm
42" - 44"
107 - 112cm
35" - 37"
89 - 94cm
40" - 42"
101 - 107cm
Extra Large6’2" - 6’4"
187 - 193cm
44" - 46"
112 - 117cm
37" - 39"
42" - 44"
107 - 112cm
2XL6’3" - 6’5"
189 - 196cm
46" - 48"
117 - 122cm
39" - 41"
44" - 46"
112 - 117cm
3XL6’4" - 6’6"
194 - 198cm
48" - 50"
122 - 127cm
41" - 43"
46" - 48"
117 - 122cm

Please be aware these sizes are for guidance only.

O’Three use only the best neoprene.  Its super supple qualities will ensure that all of the measurements above will have a degree of leeway.

If you are not sure on the size that you might require, please do not hesitate to give us a call on 01305 822820 or use our contact form here.


Black Blue with Blue Accent Graphics, Black Grey with Orange Accent Graphics


Small, Medium, Medium Tall, Medium Large, Large, Extra Large, 2XL, 3XL

2 reviews for 65 Diving Semi-Dry Wetsuit

  1. Peter Kelk

    Have used this suit in the UK for a couple of dives just to try it out was amazed how warm it was (summer diving in the UK so 17C and 18C I used a 2mm short john also 03 which was perfect) have also used it for a weeks diving in Malta end of October water temp was 24C I needed no rash vest just wore the 6/5. I feel the cold but even doing repetitive dives was not chilly at all in this suit. I was advised to use a diluted jollop to help the suit on and off my arms and I can confirm that this is an essential requirement as the suit is a very good fit. Great product.

    • Dave

      Thanks for the great review Peter..

  2. Lee Dowling

    Absolutely fantastic suit! Took it to Stoney Cove on 6th September to try it out. No thermal layer, just a rash vest and I was toasty warm. And as for the service I received; second to none! Absolutely fantastic. They were friendly and really helpful. When I come to buy a dry suit, I will DEFINITELY be buying it from O’three! You guys have got a lifetime customer now. 🙂

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