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The fastest wetsuit ever.

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Wind-tunnel-tested.
Real-world-proven.

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The most popular swimskins in Kona.

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Train smarter. Swim faster.

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Men's SIM Pro II Buoyancy Shorts

Color: Black / Acid Lime
Black / Acid Lime
Size: Extra Small

OUTLET ITEMS: Our standard 2-year warranty still applies. Exchanges & returns are eligible for store credit, but outlet items cannot be refunded directly.

By giving you a small assist in buoyancy at the hips, the SIM Pro II lets you focus on the more nuanced parts of your stroke (timing of kick, pull and body rotation) and on efficient forward propulsion and drag reduction—rather than fighting to keep your hips up. Plus, they make training more fun and get you to the pool more often. We challenge you to wear SIM Shorts regularly and not improve your swim.

Size Chart Size Chart

Updated Construction

Yamamoto SCS Coated Stretch Knit - Easier to Get Solid, Snug Fit - Seals Out Water Better

Showing seal that keeps water out

Optimized Fit

Optimized Length and Leg Openings - Higher Rise in Back - More Comfortable Front

Showing the new fit on a swimmer

Updated Graphics

Added Color Hit to Back Waistband for Improved Technique Evaluation From the Pool Deck

Color added for visibility and evaluation

Train Like You Race® With the SIM Pro II

The SIM is the first practical triathlon and swim training tool to mimic the body position and experience of a wetsuit swim by lifting you up — without overheating from wearing a wetsuit in an 80°F pool. This patent-pending suit is a game changer. It's better than a pull buoy, because it lets you kick and turn naturally. It's also gives just a touch of warmth for those cold morning workouts. The SIM makes every swim a race-specific training workout. Once you try it, you won't ever want to go back. Note, these shorts are designed for the pool and should have excellent durability if you rinse them after use with fresh water and dry them thoroughly.

SIM PRO II SIZE TIP

Fit tip: SIM Shorts are neoprene and will loosen slightly in the water. However, they do have a drawcord for adjustment.

SIM PRO II DETAILS

Get the Fastest Body Position

The SIM Pro lifts up your hips just like a wetsuit, putting you in the fastest position possible and helping your body develop the muscle memory you need on race day. Most top wetsuit manufacturers focus on buoyancy alone.  Sure, wetsuits help lift you up, but that's not enough – and in some cases it can really get in the way of fast swimming. To get the fastest body position, you have to remove buoyancy, mass and resistance from the places you don't want it. With the SIM Pro, we add buoyancy to the hips and legs, creating the fastest position possible.  We also use Yamamoto's SCS coating to further reduce form drag.  We're confident you'll feel the ROKA difference as soon as you jump in the water.

Improve Your Technique

If you want to swim faster with less effort, then rotation matters a LOT.  A fast freestyle requires effective rotation along your centerline to generate power and speed in the most propulsive phase of your stroke.  The Maverick Pro leverages basic laws of physics.  We call our application of those laws "RS2" - the ROKA Speed Stripes.  It's science, and it will make you faster.

The majority of the suits on the market get this problem dead wrong.  We did a LOT of trial and testing to get this right.  Many suits, even the most expensive, add buoyancy to the lateral or outside parts of a wetsuit, but using basic physics, it's easy to see that it is the equivalent of adding weights to your cycling shoes and pedals!  It inhibits the power phase of your stroke, makes it really hard for you to rotate properly, and makes you expend more energy.  Our patent-pending suit design enhances the power phase of your stroke and encourages quick, easy rotation along your centerline.  And if you over-rotate when you swim, you will be able to feel that more easily in our suit.  All of that translates to faster swimming with less effort.

Tech Specs

Yamamoto Neoprene

For the SIM Pro II, we use the exact same materials as its big brother, the Maverick Pro Wetsuit. This provides the exact feel you'll have on race day. "Training Like You Race" begins with developing precise muscular and neurological adaptations — the SIM Pro II lets you do that.

The SIM Pro II is 100% premium Yamamoto neoprene from Japan.  We use Yamamoto #39 SCS coated neoprene in varying thicknesses and use Yamamoto's Aerodome neoprene on the centerline (front and back).  #39 is a long-time favorite in premium triathlon suits and offers an excellent balance of performance and cost.  For the waistband, we use an advanced textile from Yamamoto to provide a better seal from water entry and folded neoprene can provide.  SCS is Yamamoto's proprietary hydrophobic surface coating.  For the centerline panel, Yamamoto Aerodome is a sandwiched neoprene that contains a perforated layer between two solid layers.  This composition traps air inside little chambers and improves buoyancy while reducing weight.  

Frequently Asked Questions (FAQ)

Q: What is the difference between the SIM Pro II and the original SIM Pro?

There are two main differences:

  1. We've added a new textile waistband construction that allows for a better seal so that less water enters the suit when diving into the pool, pushing off a wall, or swimming.
  2. We've also fine tuned the fit to provide more comfort and to cover more body types.

Q: Can I wear the SIM in a race?

  • The SIM is considered by USAT rules to be the same as a wetsuit. Therefore, you may wear the SIM in a race where wetsuits are permitted, but you may not wear it in a non-wetsuit race.

Q: Can I wear the SIM in the pool?

  • Yes, absolutely. The SIM was designed for pool swimming. Just rinse it with fresh water after use and hang dry inside out.  

SIM Size Chart

WAIST: 26" - 27"
HIPS: 30" - 32"
XS
WAIST: 28" - 29"
HIPS: 33" - 35"
S
WAIST: 30" - 32"
HIPS: 36" - 38"
M
WAIST: 32" - 34"
HIPS: 39" - 41"
L
WAIST: 34" - 36"
HIPS: 41" - 43"
XL
WAIST: 36" - 38"
HIPS: 43" - 45"
XXL
WAIST: 66cm - 69cm
HIPS: 76cm - 82cm
XS
WAIST: 70cm - 74cm
HIPS: 83cm - 90cm
S
WAIST: 75cm - 81cm
HIPS: 91cm - 97cm
M
WAIST: 81cm - 86cm
HIPS: 98cm - 104cm
L
WAIST: 86cm - 91cm
HIPS: 104cm - 109cm
XL
WAIST: 91cm - 96cm
HIPS: 109cm - 114cm
XXL

Overall rating: 4.8035398 / 5 from 1130 reviews.

AI Generated Review Summary

The Men's SIM Pro II Buoyancy Shorts provide great buoyancy, improve swimming speed, and offer a sleek look. Customers appreciate the excellent fit and quality, though some experienced sizing issues. The shorts enhance training and make swimming more enjoyable.

Summary topics

  • Swimming Performance (8%): It was observed by customers that the swim shorts greatly improved their swimming speed and ease of use.
  • Product Aesthetics (3%): Customers loved the look of the product, with many describing it as great, amazing, and sleek.
  • Product Fit (19%): A significant amount of customers expressed appreciation for the great fit of the product, mentioning it multiple times.
  • Product Quality (12%): It was noted by customers that the quality of the product is consistently great, excellent, and high.
  • Buoyancy Performance (9%): It was noted by customers that the buoyancy provided by these shorts is great and well worth the price.

Review topics: [].

Review highlights

  • "high quality materials, good fit" — Scott S.
  • "Quick delivery - all the way to Iceland - comfortable fit and swimming is fun at lastTx ROKA" — Bjorn
  • "Gives me a much better position with natural form than any other device and has a great look and feel in the pool!" — Navid A.

Reviews

Game Changer

"I noticed that I was able to maintain my pace more comfortably and swim for longer periods without feeling as restricted. The shorts provide excellent freedom of movement while still offering the support needed during longer training sessions. The quality and attention to detail are exactly what I would expect from a high-performance swim product. If you’re looking for swim shorts that are comfortable, durable, and designed with performance in mind, I highly recommend the ROKA SIM PRO 3. They have become a valuable part of my swim training and have helped me feel faster, more efficient, and more comfortable in the water."

— Jason C. (5/5)

Awesome

"I committed to a triathlon fairly last minute and training began right away. I quickly found out how much improvement I needed to make with my swimming and some quick research made these look like a no brainer. I picked up a pair and they have been extremely helpful with getting my form dialed in and are very helpful while training in a TX summer for an open water race in wetsuit water on the coast this fall."

— Dane T. (5/5)

Amazing shorts

"Great fit! Maybe considered getting a size up but the Large I got fits perfectly really as per sizing guidance"

— Jobert F. (5/5)

Game Changer

"Definitely want to size up, great fit other than that. Keeps my hips elevated on the swim. Let's me focus on my stroke on all my training sessions in the pool."

— Phillip Z. (5/5)

"These shorts are nothing short of amazing! They have absolutely helped me maintain hip position and level out my legs from the first time Inused them. For context I’m 5’5”, 150lbs"

— Adolph (5/5)

Amazing shorts!

"Used in my first triathlon of olympic distance. felt great and fit just right. I bought a size medium and I usually wear a 32 side swim suit or pant. 180cm tall"

— Tyler B. (5/5)

The best swim I had in ten plus years doing triathlons

"I tried first in the pool and cut my times by 4-5 minutes. I finally used it race day and finished my Olympic swim in a record time for me almost 6 minutes faster."

— Jorge H. (5/5)

"Fits well and comfortable. Xs for 5'11 , 135-140 lbs. No effort floating. Not racing for anything, just routinely swimming from my paddle board. Traps heat rather well."

— Caleb (5/5)

Delivery and qualified

"It’s delivered very quickly and with great quality product."

— Benildus V. (5/5)

Great Overall Purchase

"Very great shorts especially for helping keep hips up when swimming. I always struggled with keeping my hips up and these helped out greatly. I am a 35” waist and ordered XL’s. I might order XXL next time because they’re very tight but I understand that’s the idea."

— Michael H. (5/5)

Q&A

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