How to Do an Underwater Dolphin Kick: A Beginner's Step-by-Step Guide

Why Underwater Dolphin Kicks Matter

The underwater dolphin kick is often called the fifth stroke of swimming because elite swimmers can move faster underwater than they can on the surface. This speed advantage is real and measurable: swimmers can reach approximately 10 km/h underwater compared to about 8 km/h on the surface. That difference might sound small, but it translates directly to faster starts, faster turns, and faster finishes in races.

Beyond pure speed, the dolphin kick produces about 25% more propulsion than a freestyle kick using the same energy. What does this mean for you as a beginner? It means that learning this skill efficiently—with proper technique and rhythm—can shave valuable seconds off your times without requiring you to work harder. The key is understanding that speed comes from leverage, flow, and timing, not from thrashing harder.

The underwater dolphin kick is legal in several events. It is required in butterfly, where it powers both the stroke and the underwater phase after the start and turns. In freestyle and backstroke, you can use up to 15 meters of underwater dolphin kicks after each start and turn before you must break the surface and swim on top of the water. You also get one simultaneous leg kick during the breaststroke pull-out after the start. This 15-meter rule exists to keep the race fair and maintain the spirit of each stroke—swimmers cannot stay underwater the entire race.

Master this skill and you’ll surprise yourself at how much faster you move off the wall and off the blocks.

Ready to learn what the dolphin kick is and how your body creates that propulsion? Next, you will discover the definition, the legal requirements, and the core mechanics that make this skill work.

What Is a Dolphin Kick? Definition & Basics

A dolphin kick is a simultaneous up-and-down leg motion where both legs move together as one unit, with only a slight bend at the knees. Unlike a flutter kick (used in freestyle), where your legs alternate, the dolphin kick requires your legs to move in sync, creating a wave-like undulation that flows through your entire body from your chest down to your feet.

The name can be misleading at first because it sounds like only your legs are involved. In reality, the power comes from your core, hips, and chest working together to create that wave motion. Your legs are simply the finishing point of a much larger movement pattern. Think of your legs as the tail end of a whip—they extend the power generated by your upper body.

Where the Dolphin Kick Is Used

The underwater dolphin kick appears in several places during competitive swimming:

• Butterfly stroke: The dolphin kick is required for every stroke cycle and is the heartbeat of the event.
• Freestyle and backstroke: After the starting dive and after every turn, swimmers are allowed to use dolphin kicks underwater before surfacing.
• Breaststroke pull-out: After the dive, breaststroke swimmers perform a single dolphin kick followed by breaststroke movements.

The underwater kick after turns generates more speed with less resistance than surface swimming. This is why mastering it gives you a real edge in racing.

Legal Rules: What FINA Says

To keep your dolphin kick legal in competition, you need to understand two core rules. The movement must be simultaneous—both legs move together at the same time, not alternating. However, your feet do not have to be at exactly the same level. One foot can be slightly higher or lower than the other, which is good news for beginners who worry about mirror-perfect symmetry. As long as your legs move together (not one at a time) and you stay within the 15-meter underwater limit after starts and turns, you are within the rules.

Next, you’ll learn how your body actually creates that wave motion and which muscles drive each phase of the kick.

How Your Body Moves: The Mechanics Explained

The dolphin kick technique relies on a full-body wave motion, called undulation, that travels from your chest to your feet. It’s not just your legs working—your entire body creates this wave to produce the fastest underwater kick possible.

Think of it as a kinetic chain, where each part of your body passes the motion along in sequence. Here’s the step-by-step breakdown with simple cues to feel it right away.

The Kinetic Chain Sequence

1. Start with a chest press: Push your chest down toward the pool bottom. This initiates the downkick and sets the wave in motion.
2. Hips follow the chest: Let your hips drop naturally right after, keeping the timing coordinated—no forcing it. This hip movement keeps the wave flowing smoothly.
3. Legs extend and ankles finish: Your legs straighten with minimal knee bend, and your feet accelerate to complete the motion. This creates the whip effect, where a small movement at the top leads to faster, larger motion at your feet—your secret weapon for propulsion.

For the return, the upkick is just as crucial. Your glutes, hamstrings, and calves lift your legs back up, generating equal power. Elite swimmers spend the same time on both phases. If you neglect the upkick, you limit your speed.

To make this efficient, hold a streamline position: ears squeezed between biceps, arms locked straight overhead, body tight like a pencil. A loose streamline makes the same kick feel stuck because it adds drag, while a tight one lets the wave glide freely.

Two quick terms on wave timing: wavelength is how long the wave stretches along your body, and amplitude is how high it rises and falls. Focus on smooth timing over huge movements—these make your dolphin kicks powerful without wasting energy.

Here’s a simple comparison of the two phases to lock in the feel:

Practice this sequence slowly on land first to feel the whip effect snap at your toes. Once you get the coordination, you’ll unlock the technique that turns your underwater kicks into a speed machine. Next, head to Phase 1 to build it on dry land with specific drills.

Phase 1 – Start on Dry Land (Weeks 1–2)

Before jumping into the pool, spend Weeks 1–2 building the foundational strength and body awareness you need. This dryland phase awakens your hip flexors, quads, glutes, and core while teaching you the basic motion pattern without water resistance getting in the way.

These simple exercises help you gain confidence and avoid common beginner frustrations like struggling to keep your legs moving together. Do 2–3 sessions per week, keeping each one to 10–15 minutes.

Pre-Kick Body Checklist

Before you start any dryland exercise, run through this quick check:

• Streamline position engaged: arms locked overhead or at sides, no wiggle.
• Head neutral: ears between shoulders, not tipped back or forward.
• Shoulders relaxed: not shrugged up toward ears.
• Abs engaged: tense your core as if bracing for a punch.
• Toes pointed: plantarflex your feet (toes reaching away from your body).
• Knees soft, not locked: slight flex, not rigid.

Key Dryland Exercises

Lie on your back on a comfortable surface like a yoga mat, with your arms relaxed by your sides and palms facing down. Keep your legs straight and together throughout.

1. Leg lifts: 3 sets of 10 reps. Slowly lift both legs together 6–8 inches off the ground, then lower them with control. Pause briefly at the bottom before the next rep.
2. Leg holds: 3 sets of 30 seconds. Lift your legs to 6–8 inches and hold steady, breathing normally.

Rest 30–60 seconds between sets. Focus on smooth, controlled movement to mimic the wave motion.

Safety Cues and Readiness Check

A common beginner error is arching the lower back, which can cause strain. Fix this by engaging your abs and maintaining a neutral spine—imagine sliding your hand under your lower back; it should fit with light pressure, not a big gap.

You’re ready to advance to the pool when you can complete a full set of leg holds for 30 seconds without any lower back strain or shaking. If not, repeat this phase until it feels solid.

Here is a quick dryland drill checklist to guide your sessions:

• Start lying flat on your back with legs together and straight.
• Engage your abs before lifting to protect your neutral spine.
• Lift legs only 6–8 inches for controlled range.
• Keep movements slow and legs pressed together—no separating.
• Breathe normally; don’t hold your breath.
• Stop immediately if you feel lower back arching or pain.

Mastering these basics on dry land sets you up for success in the water. Next, in Phase 2, you’ll take this motion to the surface with a kickboard.

Phase 2 – Master Surface Kicks with a Board (Weeks 3–4)

Now that you’ve built a foundation on dry land, it’s time to take your technique into the water using a kickboard for stability. This phase focuses on transferring that strength into smooth, rhythmic flow while supported on the surface.

Grab a kickboard and hold it out front with arms extended straight ahead, or grip the end for more control. The kickboard gives you stability and builds confidence as you learn the sequencing—no sinking, just focusing on the motion.

Flow Drill Set: 8×25s

This is your main set for weeks 3 and 4: swim 8×25s with light dolphin kicks at an easy pace. Rest 15–20 seconds between each 25. Emphasize smoothness and feel over speed—you should sense a rhythmic wave motion traveling from your chest press through your hips to your feet, with legs moving together.

Do the sequence like this:

Repeat the entire four-25 sequence twice for a total of 8×25s. This is four-plane training—front, right side, left side, back—to build coordination in every direction.

Don’t worry if it feels awkward at first—muscle memory takes 2–3 sessions to kick in. Stick with it, and the flow will start to feel natural.

Optional Snorkel for Better Focus

A snorkel is a great add-on here. It lets you breathe continuously without lifting your head, keeping your eyes down and alignment steady. No breathing distractions means you can zero in on timing the chest press, hip rise, and leg undulation. With a snorkel, your head stays locked in streamline position, which reduces drag and lets you focus entirely on the wave. If you’re new to snorkels, just pop it in and exhale gently through your mouth as you kick.

Practice this Flow Drill Set 2–3 times per week. When you can complete all 8×25s with smooth, connected waves on both sides, you’re ready for the next step.

Mastering these surface kicks with a board prepares you perfectly for the underwater kick in Phase 3. Next, you’ll go underwater with the Building Kick Progression.

Phase 3 – Go Underwater (Weeks 5+)

Now it’s time to take your technique underwater, where you’ll build the anaerobic capacity needed for race-like efforts while keeping your streamline position tight and controlled. This phase focuses on true underwater kicks after turns, transitioning smoothly from your surface work.

Building Kick Progression: 4×75s

Perform this set three times a week, starting in Week 5. Each 75 consists of three 25s within it, with a controlled number of underwater kicks off the wall. Rest 20–30 seconds between rounds.

1. Round 1: 4 dolphin kicks off the wall, then easy swim or kick to finish each 25 (3×25 total per round).
2. Round 2: 5 dolphin kicks off the wall, then easy swim or kick to finish each 25 (3×25 total per round).
3. Round 3: 6 dolphin kicks off the wall, then easy swim or kick to finish each 25 (3×25 total per round).

Push off the wall in a tight streamline position, arms stacked over your head, head neutral between your biceps. Start your underwater kicks right after the push-off, counting them mentally to stay controlled. After your kick count, transition to easy swimming or kicking to complete the 25. With good technique, 6 kicks covers approximately 6–7 meters of distance.

For beginners, stick to a maximum of 6 kicks per push-off. This guardrail prevents overexertion, builds your anaerobic capacity gradually, and keeps you well under the 15-meter rule for legal underwater kicks after turns.

Gear Progression Timeline

Introduce gear progressively to change the feel and build confidence without masking your motion.

• Week 5–6: All natural (no fins) to develop true propulsion feedback from your body.
• Week 7–8: With fins to emphasize the wave motion and help you feel the rhythm more easily.
• Week 9+: Fins + paddles to engage your upper body while maintaining streamline.

Fins vs. no fins callout: No fins gives honest feedback on your power and efficiency, like the real feel in races. Fins build confidence and amplify the rhythm, letting you focus on flow before stripping them away.

Technique Under Fatigue

As you go underwater, fatigue will hit harder—your muscles may lag, and coordination can slip. This is normal; it’s how you build the endurance for fast underwater kicks in races. Expect your streamline to loosen slightly and your kicks to rush. Focus on mental kick counting to stay rhythmic.

Common Beginner Underwater Mistakes

Here are quick fixes for pitfalls you’ll notice first underwater:

• Rushing the kicks: Slow your tempo mentally; count to match your surface rhythm.
• Losing streamline position: Squeeze your biceps to ears and abs engaged before every push-off.
• Kicking too hard: Use the 4/5/6 count to keep amplitude controlled, not explosive.

With consistent practice, these fade as your body adapts. Next, learn to spot and correct common mistakes across all phases for smoother progress.

Progression Steps with Timeline

Common Mistakes & How to Fix Them

Even with the best intentions, beginners often fall into a few predictable patterns that slow progress or create discomfort. The good news: once you spot the error and apply the right cue, improvement comes quickly. Below are the most common mistakes, why they happen, and exactly how to fix them.

Common Mistakes Checklist

Review this checklist to identify which mistakes may be affecting your kick:

• NOT over-bending your knees; keep a smooth wave, not a scissor motion.
• NOT keeping your feet flexed; point your toes for full propulsion.
• NOT letting one leg dominate; maintain equal power both sides.
• NOT kicking too big or too small; aim for 6–8 inch hip rise.
• NOT letting feet move separately; move them together simultaneously.
• NOT lifting your head high; keep it neutral in streamline.
• NOT relying on your lower back; drive from core and hips.
• NOT neglecting the upkick; equal power both directions.

Mistake-by-Mistake Fix Guide

Below is a detailed breakdown of each error, why it slows you down, and the exact fix cue to use in the pool.

Asymmetry Diagnosis & Correction

If one leg feels significantly stronger or moves faster than the other, asymmetry is limiting your speed and control. Use this targeted approach to rebalance:

• Right leg dominant: perform 8×25 left-side-only kicks (left arm forward, right arm at your side, focus entirely on driving from your left hip). Rest 15 to 20 seconds between repeats. Do this twice per week for two weeks.
• Left leg dominant: perform 8×25 right-side-only kicks (right arm forward, left arm at your side). Same rest and frequency.
• Both legs feel equal but timing is off: use a tempo trainer set to 60 beats per minute and kick on every beat for a full 25. This locks your rhythm and forces both legs to move at the same time.
• One leg feels stiff or restricted: refer to the ankle mobility subsection below. Tightness in one ankle often creates the illusion of unequal strength.

After two weeks of side-kick correction, return to two-leg drills. You should feel a noticeable improvement in balance and symmetry.

Ankle Mobility: The Foundation of Pointed Toes

Stiff ankles are one of the most overlooked reasons beginners struggle with the dolphin kick. Tight ankles prevent you from achieving plantarflexion (full toe pointing), which reduces the surface area of your foot and limits propulsion. Flexible ankles let your feet work as full leverage tools; stiff ankles force your feet to act like shortened flippers instead.

Perform these three dryland drills three to four times per week, ideally on non-kick days or after warm-up:

• Plantarflexion stretches: sit on the pool deck with your legs extended. Loop a towel or resistance band around the ball of your foot and gently pull your toes toward your shin to feel a stretch in your shin and ankle. Hold for 20 to 30 seconds. Reverse: point your toes hard and hold for 10 seconds. Repeat 5 times per leg.
• Ankle circles: sit or stand on one leg. Rotate the other foot slowly in circles (10 clockwise, 10 counterclockwise). This improves ankle mobility and balance. Repeat on both feet.
• Towel scrunches: place a small towel flat on the floor. Using only your toes (without moving your foot), scrunch the towel toward you. Repeat 10 times with each foot. This activates and strengthens the small muscles in your feet and ankles.

After two to three weeks of daily ankle mobility work, most beginners notice significantly improved plantarflexion and reduced stiffness in the pool.

Common Aches & Fixes

Dolphin kick practice is intense on your core and hips. If you experience mild discomfort, these technique adjustments usually resolve it within a few days:

• Lower back stiffness: This is the most common beginner complaint. Cause: your abs are not engaged, so your lower back is doing the work. Fix: engage your core before every set (tense your abs for 5 seconds, then begin kicking). Focus on driving from your hips, not your spine. If stiffness persists, reduce your session volume by 25% for one week, then gradually rebuild.
• Hip flexor fatigue: This happens when you over-emphasize the downkick and neglect the upkick. Fix: balance your downkick and upkick time equally. Don’t emphasize only the downbeat—spend as much effort pressing your hips down as you do driving your glutes and hamstrings up. If fatigue is severe, add a rest day and return to Phase 2 drills (board, easy pace, 15 to 20 second rest between repeats).

Prevention is always easier than recovery. Engage your core, balance upkick and downkick, and progress gradually over 8 to 12 weeks. Your body will adapt, and discomfort will disappear.

Sample Beginner Workout Week

Now that you’ve built your foundation through the phases, here’s how to put it all together in a simple weekly plan. This beginner schedule integrates the flow drill and building kick progression into three focused sessions, with built-in rest for recovery. Each session keeps things short and sustainable.

Monday: Flow Drill Day

Focus on rhythm and body awareness with the 8×25 flow drill sequence (front, right side, left side, back; repeat twice).

• Warm-up: 200 easy (any stroke you like)
• Main set: 8×25 flow drill with 15-sec rest
• Cool-down: 100 easy

Wednesday: Building Kick Day

Focus on underwater endurance with the 4×75 building kicks (all natural for now, using 4/5/6 kicks per round).

• Warm-up: 200 easy
• Main set: 4×75 building kicks with 25-sec rest
• Cool-down: 100 easy

Friday: Mixed Drill Day

Focus on transition confidence by alternating surface and underwater kicks.

• Warm-up: 200 easy
• Main set: 6×50 (board kick 25 + underwater kick 25) with 20-sec rest
• Cool-down: 100 easy

Plan for 2–3 rest days per week—use them for light stretching or walking to let your muscles adapt and recover. This prevents fatigue and helps your body learn the motion.

Progress your gear along this timeline to build strength gradually:

• Weeks 5–6: All natural (no gear).
• Weeks 7–8: Add fins to main sets.
• Weeks 9+: Fins + paddles.

Rotate through this weekly drill checklist to keep sessions fresh and balanced. Check off what you hit each week:

• Flow drill on stomach (front position)
• Flow drill on right side
• Flow drill on left side
• Flow drill on back
• Building kicks off the wall (4/5/6 kicks)
• Mixed board-to-underwater transitions

Frequently Asked Questions

Q: When am I allowed to use underwater dolphin kicks in a race?

A: In butterfly, you must use the dolphin kick for every stroke and underwater phase. In freestyle and backstroke, you can use up to 15 meters of underwater kicks after each start and turn before surfacing. In breaststroke, you get one simultaneous dolphin kick during the pull-out after the start.

Q: Why do my legs feel uncoordinated when I dolphin kick?

A: Uncoordinated legs usually mean your timing is off or one side is stronger than the other. Use a tempo trainer set to 60 beats per minute and kick on every beat to lock your rhythm. Also try side-kick-only drills to identify and fix imbalances.

Q: Can I use the underwater dolphin kick during breaststroke?

A: Yes, but only during the pull-out after the start. You perform one simultaneous dolphin kick, then immediately transition to breaststroke movements. You cannot use dolphin kicks during the stroke itself or after turns in breaststroke.

Q: How long does it take to master the underwater dolphin kick?

A: With consistent practice—2 to 3 sessions per week—you can develop a smooth, functional kick in 8 to 12 weeks. Mastery takes longer, but noticeable improvement appears in 4 to 6 weeks.

Q: Why is ankle flexibility important for dolphin kicking?

A: Plantarflexion (toe pointing) requires ankle mobility. Stiff ankles reduce the surface area of your foot, limiting propulsion. Flexible ankles let your feet act as full leverage tools, not shortened flippers. Ankle mobility drills take 2 to 3 weeks to show results.

Q: Do my feet have to be at exactly the same level when I dolphin kick?

A: No. Your feet do not have to be at exactly the same level. One foot can be slightly higher or lower than the other. The key rule is that your legs must move simultaneously—together at the same time, not alternating.

Q: What if one leg is much stronger than the other?

A: Use side-kick-only drills to build the weaker side. Kick on one side for 8×25 (the non-dominant arm forward), rest 15 to 20 seconds between repeats, and repeat twice per week for two weeks. Then return to two-leg drills and retest your symmetry.

Q: Should I use fins when I practice dolphin kicks?

A: Fins are helpful for learning rhythm and confidence, but they mask your true propulsion. Progress gradually: weeks 5–6 all natural, weeks 7–8 with fins, weeks 9+ fins + paddles. No-fin drills give you honest feedback on your power.

Pro Tips & Next Steps

You now have a complete path from dryland to underwater mastery. Before you dive into your training week, anchor these high-impact rules into your practice mindset.

Core Technique Reminders

• Keep your arms stable and shoulders relaxed. Stable shoulders make hip motion easier and cleaner.
• Focus on your feet. They accelerate most during the kick and create the whip effect that drives speed.
• Maintain streamline position. Tight alignment reduces drag, so every rep matters.
• Train your upkick and downkick equally. Elite swimmers generate power on both the down and up phases; beginners often neglect the upkick and miss 50% of their potential speed.
• Practice consistently: 2 to 3 sessions per week for 8 to 12 weeks delivers noticeable improvement.
• Choose patience over perfection. Muscle memory takes time. Feel the wave motion before chasing speed.
• Progress gradually. Do not jump from board work to 10 consecutive underwater kicks in one week. Build amplitude and rhythm in small steps.

Your Next Step Forward

Once your basic underwater kick feels solid (around week 6 to 8 of consistent practice), learn to optimize your kickoff timing at the 6-meter rule. This means mastering when to transition from underwater kicks to your primary stroke during starts and turns. Efficient kickoff timing is where the underwater kick becomes a true race advantage.

If asymmetry persists after 4 to 6 weeks of side-kick drills and tempo trainer work, consider a session with a qualified swim coach. A coach can spot imbalances in your body position or leg timing that drills alone may not reveal. Coaching is optional but valuable if progress stalls.

You have everything you need to build a powerful, efficient underwater kick. Master this skill and you’ll open up your entire swimming potential, whether you’re racing fly, pushing hard off the wall in freestyle, or refining your backstroke. Trust the process, respect the progression, and celebrate small wins along the way. You’ve got this.