How to Make a Swimrun Pull Buoy: A Step-by-Step Guide for Beginners

Updated November 2026

Knowing how to make a swimrun pull buoy lets you build a lightweight float that you can tow or wear during swimrun training and carry through the swim leg of a race. A well-built buoy sits low and stable, gives you a visible marker in open water, and takes only a few hours of work with basic materials. This guide covers the materials, the build, and the checks that matter before you trust one in open water.

What You Need Before You Start

Gather these items before you cut anything. Most of them are available at a hardware store or a swim shop.

Shopping for one? See our guide: Top 4 Pull Buoy and Kickboard Sets for Swim Training.

• A closed-cell foam block or foam sheet, roughly 10 to 12 inches long, sized to fit between your thighs
• A sharp utility knife or foam saw
• Waterproof marine-grade adhesive or two-part epoxy
• Sandpaper, medium grit
• A strap made from webbing or a nylon belt, rated for wet use
• Stainless steel or nylon hardware for the strap connection
• A tape measure and a marker

Step 1: Size the Foam to Your Body

Start by measuring the gap between your thighs when you are standing with your legs together. Most swimrun athletes end up with a buoy between 9 and 12 inches long, but the goal is a snug fit that does not rub. Mark the foam block, then cut it with a steady, straight stroke so the edges stay square.

Step 2: Shape and Smooth the Body

Round the leading edges with sandpaper so they slide past your legs without snagging. Keep the rear section slightly thicker than the front. That profile helps the buoy stay level in the water instead of tipping forward. Wipe away foam dust before you move on, since loose particles weaken adhesive bonds.

Step 3: Attach the Strap Securely

Cut two channels or pockets through the foam at the center, then glue the strap ends into them. Use marine adhesive or epoxy and let it cure for the full time the label specifies, which is usually 24 hours for epoxy. Stitch or rivet the strap ends as an extra safeguard, since adhesive alone can fail under repeated load.

Step 4: Test Buoyancy and Stability

Test the finished buoy in a pool before any open-water use. Hold it between your legs while floating and check three things: whether it keeps your hips high, whether it stays centered without rolling, and whether the strap holds when you kick hard. If your hips sink, add foam to the rear section. If the buoy rolls, reduce the front thickness slightly.

Common Mistakes to Avoid

• Using foam that absorbs water. Closed-cell foam keeps its buoyancy; open-cell foam does not.
• Skipping the cure time. Rushing epoxy leads to weak joints.
• Making the buoy too large. Oversized builds drag and chafe the inner thighs.
• Testing only in calm water. Check it in mild chop before race day.
• Ignoring visibility. Bright or reflective trim helps boats and safety crews spot you.

Recommended Gear

If you prefer a ready-made option for pool training while you refine your homemade design, a proper training buoy helps you compare fit and feel. A marine-grade waterproof adhesive is worth having on hand for repairs. A hip-fit training float can also serve as a reference point when you test your own build. View on Amazon View on Amazon View on Amazon

For pool-based practice with a commercial buoy first, see Swimming With a Pull Buoy: A Step-by-Step Guide for Better Pool Training. If you are still choosing between models, Speedo Team Pull Buoy: How to Choose and Use One for Pool Training (2026) explains what to look for in fit and foam density.

FAQ

Can I use any foam to make a swimrun pull buoy?

No. Choose closed-cell foam, which resists water absorption and keeps its lift over time. Open-cell foam soaks up water and loses buoyancy quickly.

How long should a homemade buoy last?

Durability depends on foam quality, adhesive, and how often you use it. Inspect the strap joints and foam surface before each session and replace any part that shows cracks, soft spots, or loosening.

Do I need to test my buoy before racing?

Yes. Test it in a pool for stability and strap strength, then in open water in mild conditions. If you have any doubts about safety in open water, consult an experienced coach or swim instructor before you rely on the buoy.

Conclusion

Making a swimrun pull buoy comes down to sizing the foam correctly, shaping it for stability, and anchoring the strap with cured adhesive. Test each build in a pool before taking it into open water. With careful measuring and a few checks, you will have a float that supports your training and race-day swims.

Related reading

• 6 Best Swims with Pull Buoy Options for Pool Training (2026)

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