Last Updated: March 2026

Swimrun Pull Buoy Guide: Setup, Mounting Styles & Best Practices [2026]

A swimrun pull buoy is essential gear that provides flotation when swimming in shoes, typically offering 40-50 Newtons of buoyancy compared to 15-20 Newtons for pool pull buoys. Pull buoys attach to your body via waist mounts (simple mount or lasso mount) or hip/leg mounts, staying on your back during runs and moving between your legs while swimming. The maximum legal size for ÖTILLÖ events is 32cm x 30cm x 15cm.

Swimming in trail running shoes creates significant drag that slows most swimmers by 10-20 seconds per 100 meters. A properly sized swimrun pull buoy offsets this drag by lifting your legs and hips into proper swimming position, often making you faster in shoes with a pull buoy than swimming without shoes in a pool.

Why do you need a pull buoy for swimrun?

Pull buoys solve the fundamental challenge of swimrun: swimming efficiently while wearing shoes. The added weight and drag from shoes pulls your legs down, forcing your body into a poor swimming position that increases resistance and slows your speed.

Buoyancy advantage: Swimrun-specific pull buoys provide 40-50 Newtons of flotation (some models exceed 50 Newtons). Pool pull buoys typically provide only 15-20 Newtons. This difference matters significantly when you're swimming 2-6 miles in shoes across a race.

Speed gains: Testing by Swimrun Labs showed that swimmers using high-buoyancy pull buoys like the Ark Keel swim approximately 5 seconds per 100 yards faster than with standard pool buoys. Over a 3km swim section, this translates to 75-90 seconds of time savings.

Body position: A pull buoy lifts your hips and legs to the surface, maintaining the horizontal body position essential for efficient swimming. Without a pull buoy, swimming in shoes forces most athletes into a 20-30 degree decline angle that increases drag exponentially.

Legal in all races: Pull buoys are universally legal in swimrun races and actively encouraged by race directors.

What are the best swimrun pull buoys for 2026?

Based on our extensive testing and racing experience, here are our pull buoy recommendations organized by experience level and buoyancy needs. All recommendations are from the Ark Sports Keel family, which features a unique hydrodynamic shape inspired by a boat's keel with a carved "saddle" top that optimizes fit and keeps the buoy in place while swimming.

The bigger the pull buoy, the more lift and speed you get in the water. Maximum legal size for ÖTILLÖ events and most other swimrun races is 32cm x 30cm x 15cm (the Keel MEGA).

Our Top Recommendation: Ark Keel+

Price: €50 / $55
Buoyancy: High (more than standard Keel)

Extra buoyancy and faster water position for swimmers who want more power. Built for speed and performance with every swim. This is our go-to recommendation for most swimrunners. More girth than the standard Keel, which some swimmers find requires additional adductor engagement to keep in place, but the speed gains are worth it.

Best for: Most swimrunners seeking performance, experienced athletes (3+ races), larger swimmers (190+ lbs)

Maximum Performance: Ark Keel MEGA

Price: Contact Ark Sports
Dimensions: 32cm x 30cm x 15cm (maximum legal size)
Weight: 240g
Buoyancy: Maximum within race regulations

The ultimate pull buoy designed for top-level athletes willing to trade some comfort for maximum performance. The Keel MEGA is the biggest, fastest pull buoy on the market, adhering to maximum measurements set by international race rules. Developed with world-class swimrun athletes and the swimrun community. Despite its size, it fits perfectly on your back. This is the pull buoy used by Low Tide Boyz for all racing.

Best for: Competitive athletes seeking maximum speed, experienced swimrunners comfortable with larger buoys, anyone wanting the absolute fastest option

Best All-Arounder: Ark Keel (Original)

Price: $46 Dimensions: 28cm x 26cm x 12cm
Buoyancy: 46.1 Newtons

The original swimrun-specific pull buoy and the perfect "lagom" (just right) size. If you're new to swimrun, start here. It provides excellent buoyancy without straining your lower back. The distinctive shape minimizes drag while maximizing flotation. Testing showed the Keel was approximately 5 seconds per 100 yards faster than pool pull buoys. Works perfectly for both waist and hip mounting. This is the pull buoy used by Low Tide Boyz for training.

Best for: First-time swimrunners, swimmers of average build (140-190 lbs), anyone wanting a proven all-around option

Smaller Option: Ark Keel S

Price: $33

Works great in the pool and is a solid choice for younger swimrunners or adults who prefer a smaller, more manageable buoy, especially if you're new to the sport. Provides less flotation than the full-size Keel but still significantly more than pool buoys.

Best for: Smaller swimmers (under 140 lbs), youth swimrunners, those preferring less bulk

Pool/Technique Work: Ark Keel Mini

Price: $24

The smallest model, ideal for the pool, technique drills, or for swim coaches who want something compact and convenient.

Best for: Pool training, technique drills, coaches

For detailed reviews and testing data, check out our Gear Talk episodes where we break down performance metrics, comfort, and use cases.

Video Tutorials: Pull Buoy Setup & Techniques

Watch our complete pull buoy video series covering setup, mounting techniques, transitions, and race day tips:

This playlist includes 10 videos covering:

  • Simple mount setup tutorial
  • Lasso mount setup tutorial
  • Hip mount techniques
  • Transition tips (swim to run, run to swim)
  • Pull buoy comparisons and testing
  • Race day pull buoy strategies
  • Troubleshooting common issues

What are the different pull buoy mounting methods?

There are three primary mounting methods for swimrun pull buoys: simple mount (waist mount), lasso mount (waist mount variation), and hip mount. Each has advantages depending on your body type, racing style, and personal preference.

Simple Mount (Waist Mount)

How it works: A continuous loop of shock cord passes through the pull buoy and wraps around your waist. The buoy slides along the loop from your back (during runs) to between your legs (during swims).

Pros:

  • Fastest to set up (15 minutes DIY)
  • Easy transitions once you learn the movement
  • Pull buoy stays secure on lower back during runs
  • Works with any foam pull buoy
  • Most popular method among recreational swimrunners

Cons:

  • Requires practice to master the transition motion
  • Loop tension must be adjusted precisely
  • Some runners feel the buoy bouncing on long run sections

Best for: Most swimrunners, especially those new to the sport or wanting simplicity

Lasso Mount (Waist Mount Variation)

How it works: Instead of a fixed loop, the lasso mount uses an adjustable loop that tightens around the pull buoy itself when positioned between your legs.

Pros:

  • Pull buoy locks in place more securely while swimming
  • Slightly less bouncing during runs for some body types
  • Easy to adjust fit on the fly
  • Good for racing in rough water where buoy security matters

Cons:

  • Takes slightly longer to set up (20 minutes DIY)
  • Transition motion requires an extra step (loosening/tightening lasso)
  • Can be tricky to master initially

Best for: Swimmers racing in rough ocean conditions or those who want maximum security during swims

Hip Mount

How it works: The pull buoy attaches at hip level rather than waist level, typically using elastic straps or specialized mounting systems.

Pros:

  • No waist pressure or restriction
  • Some swimmers find it more comfortable for breathing
  • Can work well for specific body types

Cons:

  • Less common, so fewer resources and tutorials available
  • Pull buoy positioning during runs can be awkward
  • Transition mechanics differ significantly from waist mounts

Best for: Swimmers who find waist mounts uncomfortable or restrictive

Our recommendation: Start with the simple mount. It's the most common method with the most resources available, and the transition technique works reliably for most body types. Once you're comfortable with the simple mount, you can experiment with the lasso mount if you want more security in rough water.

How do you set up the simple mount?

The simple mount takes about 15 minutes to create and uses basic materials available at any hardware store. This is our preferred and recommend mounting style for most people.

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Materials Needed

  • Pull buoy: Any foam swimrun pull buoy (we recommend Ark Sports Keel or Keel+)
  • Shock cord: 3-4mm diameter elastic cord, approximately 6-7 feet long (also called paracord or bungee cord)
  • Plastic drinking straw (optional but recommended to protect the pull buoy from wear)
  • Screwdriver or awl: For making holes in the pull buoy
  • Lighter: To seal the shock cord ends and prevent fraying
  • Scissors: To trim excess cord and straw

Step-by-Step Instructions

Step 1: Make the holes

Use a screwdriver or awl to create two holes through the pull buoy, positioned about 2-3 inches apart near the center of the buoy. The holes should go completely through the buoy from top to bottom. Go slowly and carefully to avoid tearing the foam.

Step 2: Prepare the straw (recommended)

Cut the plastic drinking straw to the width of the pull buoy. The straw protects the foam from the shock cord cutting into it over time, significantly extending the life of your setup. This step is optional but highly recommended.

Step 3: Thread the shock cord

If using a straw, thread the shock cord through it first. Then thread both the straw and cord (or just the cord if skipping the straw) through both holes in the pull buoy. You should have two loose ends of shock cord coming out of the pull buoy.

Step 4: Tie and adjust

Tie a loose knot with the two ends of the shock cord. Put the loop around your waist and adjust the tension so the pull buoy sits comfortably on your lower back without excessive slack. The buoy should fit snugly between your thighs when pulled forward, but the loop shouldn't be so tight that it restricts breathing or movement.

Pro tip: Test the fit by doing a few practice transitions. You should be able to easily slide the buoy from back to front and vice versa.

Once adjusted to your preferred tension, tighten the knot securely and pull hard on all ends to set it.

Step 5: Seal the ends

Use a lighter to carefully melt the cord ends, sealing any stray fibers to prevent fraying. Melt until the fibers fuse together, then blow out the flame immediately. Repeat on both loose ends.

Maintenance: Inspect the shock cord before each race for fraying or wear. Replacement shock cord costs under $5 and takes 10 minutes to swap out. A properly constructed simple mount typically lasts an entire race season (10-15 races) or longer.

How do you set up the lasso mount?

The lasso mount takes about 20 minutes to create and provides slightly more security than the simple mount during swims.

Materials Needed

Same materials as the simple mount:

  • Pull buoy
  • Shock cord (6-7 feet)
  • Plastic straw (optional)
  • Screwdriver or awl
  • Lighter
  • Scissors

Step-by-Step Instructions

Step 1: Identify mounting position

Choose where you want the lasso attachment point on your pull buoy. We recommend the upper quadrant of the buoy for optimal balance.

Step 2: Create the hole

Using a long screwdriver, carefully push through the pull buoy at your chosen position. Go slowly and make sure the screwdriver comes out the other side. Wiggle it slightly to enlarge the hole, which helps with Step 3.

Step 3: Insert the straw

Work the plastic straw into the hole you just made. The straw should pass completely through the pull buoy, keeping the opening neat and protecting the foam from the shock cord.

Step 4: Thread the shock cord

Feed the shock cord through the straw. With the end of the cord that just passed through, tie a tight double knot. This knot will stay on one side of the pull buoy.

Step 5: Create the lasso loop

Pull the straw back out carefully. Use scissors to cut the shock cord, leaving yourself several extra inches of length (you can always make it shorter, but you can't make it longer).

Tie the two loose ends together to create an adjustable loop. The loop should be large enough to fit around your waist comfortably but tight enough that the pull buoy sits securely on your lower back.

Step 6: Test and adjust

Put the loop around your waist with the pull buoy on your back. Practice pulling it forward between your legs and sliding it back. Adjust the loop size as needed. The lasso should tighten around the buoy when positioned between your thighs.

Step 7: Seal the ends

Melt the cord ends with a lighter to prevent fraying, just like with the simple mount.

How do you use a pull buoy during transitions?

Mastering pull buoy transitions is essential for efficient swimrun racing. The movement becomes automatic after a few practice sessions.

During Runs

Keep the pull buoy positioned on your lower back within the waist loop or lasso. The buoy should sit comfortably without bouncing excessively. Most runners position it at the natural curve of their lower back where it stays secure during trail running.

Run-to-Swim Transition

Step 1: As you approach the water, reach back and grab the pull buoy from your lower back.

Step 2: Pull it forward through the loop and position it between your thighs while still on land or in shallow water.

Step 3: Wade into the water and get horizontal immediately. The buoyancy will try to float the buoy to the surface, so establish your swimming position quickly.

Pro tip: For high-buoyancy buoys like the Ark Keel MEGA, you need to "drown" the pull buoy by getting horizontal fast. If you wade too far before swimming, the buoyancy can make positioning awkward.

Swim-to-Run Transition

Step 1: As you exit the water, release the pull buoy from between your thighs.

Step 2: While the buoy is still in front of you (floating in the loop), organize it so it's not tangled.

Step 3: Slide the buoy back to your lower back as you start running.

Pro tip: It's easier to organize and slide the buoy to your back when it's in front of you rather than trying to pack it away behind you. Let it float forward first, then slide it back.

Practice Makes Perfect

Before your first race, practice the transition motion on land 10-15 times. Then practice in open water during training swims. The movement pattern becomes muscle memory quickly, and you'll soon execute transitions without thinking about them.

For detailed transition techniques and video demonstrations, check out our Swimrun Transitions: A Step-by-Step Guide.

Frequently Asked Questions About Swimrun Pull Buoys

Q: What's the difference between the simple mount and the lasso mount? A: The simple mount uses a fixed waist loop where the pull buoy slides along the loop from back to front. The lasso mount uses an adjustable loop that tightens around the pull buoy itself when positioned between your thighs. Both work well; the simple mount is slightly faster to set up and easier for beginners, while the lasso mount provides more security in rough water conditions.

Q: How tight should the waist loop be? A: The loop should be snug enough that the pull buoy doesn't bounce excessively on your lower back during runs, but loose enough that you can easily slide the buoy forward between your legs for swimming. Most swimmers find a loop that sits at their natural waist works best. Test the fit by doing a few practice transitions before your first race.

Q: Can I use a regular pool pull buoy for swimrun? A: Yes, but swimrun-specific pull buoys offer significantly more buoyancy, which is important when swimming in shoes. Regular pool buoys provide 15-20 Newtons of flotation; swimrun buoys like the Ark Keel provide 46+ Newtons. For your first race, a pool buoy works fine, but upgrading to a swimrun-specific buoy makes a noticeable difference in swim speed and body position.

Q: Do I need to use a straw inside the pull buoy when setting up a mount? A: The straw is optional but highly recommended. It prevents the shock cord from cutting into the foam over time, significantly extending the life of your pull buoy setup. A standard plastic drinking straw works perfectly and costs pennies.

Q: How long does a pull buoy mount setup last? A: With proper construction (sealed ends, straw protection), a simple mount or lasso mount typically lasts an entire race season (10-15 races) or longer. Inspect the shock cord before each race for fraying or wear. Replacement shock cord costs under $5 and takes 10-15 minutes to swap out.

Q: What's the maximum legal pull buoy size for races? A: ÖTILLÖ World Championship rules set the maximum at 32cm x 30cm x 15cm (the Ark Keel MEGA size). Most other swimrun races follow the same standard. Larger buoys provide more flotation and faster swim times, but can feel bulky during runs. Test different sizes in training to find your preference.

Q: Should I get the Ark Keel, Keel+, or Keel MEGA? A: For most swimrunners, we recommend the Keel+ as the best balance of speed and comfort. If you're new to swimrun, start with the standard Keel and upgrade later if you want more speed. The Keel MEGA is for competitive athletes willing to trade some comfort for maximum performance. Smaller swimmers (under 140 lbs) should consider the Keel S.

Q: How much faster will I swim with a pull buoy vs without one? A: Testing shows that high-buoyancy pull buoys (Ark Keel family) make swimmers approximately 5 seconds per 100 yards faster compared to pool buoys, and 10-15 seconds per 100 yards faster compared to swimming in shoes without any pull buoy. Over a 3km swim section, this translates to 90-150 seconds of time savings.

Q: Can I race without a pull buoy? A: Technically yes, but it's not recommended. Swimming in trail running shoes without a pull buoy is extremely difficult and slow. The shoes create significant drag that pulls your legs down, forcing your body into a poor swimming position. Nearly all competitive swimrunners use pull buoys, and they're legal in every swimrun race.

Q: Where should I buy an Ark Sports pull buoy? A: Ark Sports pull buoys are available directly from Ark Sports and through select swimrun retailers. Check our Complete Swimrun Gear Guide for current purchasing links and recommendations.

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