Swim training can feel like uncharted water, even for experienced triathletes. These four structured swimming workouts, built by IRONMAN Master Coach Matt Dixon of Purplepatch Fitness, develop the endurance, pace control, and technique you need to get swim-fit this season. Each one scales up or down, so a beginner and a seasoned racer can swim the same set at their own level. They are ideal for pre-season, when swimming makes up the biggest share of your training, but they work any time you want to build a stronger swim base.
How A Structured Swim Workout Is Built
Every workout below follows the same simple shape. Knowing the parts makes any swim session easier to read and to scale.
- Warm-up. Easy swimming to loosen up and raise your heart rate gradually. Mixing in a non-freestyle stroke like backstroke or breaststroke every few laps protects your shoulders and balances your body.
- Pre-set. A short block of shorter swims that wakes up your stroke and builds speed before the hard work. This is where you focus on technique, often with a pull buoy and a snorkel so you can hold a long body line and feel your catch.
- Main set. The heart of the workout. This is where you build endurance and practice holding pace across intervals, with set rest times off the pace clock.
- Cool-down. Easy swimming at the end to flush your arms and bring your heart rate down. Always finish with one, even when you are short on time.
How To Read The Pace Clock
These workouts run on a pace clock, the large clock on the pool wall. "On 1:40" means you start each repeat when the clock hits that time, and the faster you finish, the more rest you earn before the next one starts. Reading the clock keeps your sets honest and your rest consistent.
A few of the sets land on half-numbers like 1:22.5, which is a great way to sharpen your clock-reading because you cannot just watch the top of the minute. You will also see a "swimmer's minute," which simply means take an extra 30 to 60 seconds of rest. If pacing off the clock is new to you, build that skill first with IRONMAN's guide to mastering the pace clock, then add these sets.
How To Choose The Right Workout
All four build endurance, but each has its own flavor. Pick the one that matches your goal for the day, then scale the distances and intervals to your level.
- One-One-One Up is the biggest endurance builder, with a long, steady main set. Best when you want volume and pace control.
- It's The Halves That Count sharpens your clock-reading with tighter, descending sets. Best for race-pace feel and focus.
- Broken Swims alternates easy distance with fast 100s. Best for learning to hold speed when you are already tired.
- Lucky Number 8 mixes pulling, descending intervals, and short sprints. Best for variety and a fun, mentally engaging session.
Beginners should start with fewer rounds, longer rest, and an easier interval. There is no prize for finishing a set you cannot hold form on, so cut it down and build up over the weeks.
The 4 Swimming Workouts
All distances are in meters. Take the gear notes as a guide, not a rule: a pull buoy, a kickboard for kick sets, a swimmer's snorkel, and goggles that fit are the most useful tools for these sets.
1. One-One-One Up
Focus: endurance and pace control. Total: about 4,800m.
Warm-up: 10 min easy swimming, with every fourth lap non-freestyle if possible.
Pre-set: 200 / 100 / 2x150 / 2x75 / 3x100 / 3x50 / 4x50 / 4x25 with a pull buoy and a snorkel, focusing on a long body and catching the water. Build speed as you progress, up to 95 percent effort on the 25s. Take 5 to 10 seconds rest between each repeat.
Helpful hint: the odd reps decrease by 50 each time while the number of repeats grows (1x200, 2x150, 3x100, 4x50). Each even rep is half the distance of the odd rep before it.
Main set: 33x100 using three separate intervals. Hold a strong, sustainable pace on the shorter intervals, and let the pace and stroke rate ease on the "recovery" 100s.
- 100-100-100 on 1:50 / 1:45 / 1:40
- 100-100-2x100
- 100-100-3x100
- 100-100-4x100
- 100-100-5x100
- 100-100-6x100
Pick intervals that fit your ability, keep the first swim of each line as recovery, and aim for 5 to 7 seconds rest on the tightest one. To shorten the set, stop after 4 or 5 rounds. Main set total: 3,300m.
Cool-down: 200 to 300m easy, mixing in backstroke to flush your arms and drop your heart rate.
2. It's The Halves That Count
Focus: clock-reading and race-pace feel. Total: about 4,000m.
Warm-up: 10 min easy swimming.
Pre-set: 200 / 2x150 / 4x100 / 6x50, increasing speed as the distance drops, with a pull buoy and a snorkel.
Main set:
- 200 on 3:00, straight into 8x100 on 1:22.5
- Take a swimmer's minute (an extra 30 to 60 seconds)
- 200 on 2:55, then 6x100 on 1:20
- Swimmer's minute
- 200 on 2:50, then 4x100 on 1:17.5
- Swimmer's minute
- 200 on 2:45, then 2x100 on 1:15
Helpful hint: on the 1:22.5 set, each odd repeat starts on a 0 or 5 (0, 45, 90), which makes the half-numbers easier to track. Main set total: 2,800m.
Cool-down: 200m easy.
3. Broken Swims
Focus: holding speed when tired. Total: about 4,600m.
Warm-up: 10 min, with every fourth lap non-freestyle.
Pre-set: 2x200 / 2x175 / 2x150 / 2x125 / 2x100 / 2x75 / 2x50 / 2x25. Swim the odds easy and build pace on the evens, with 5 to 10 seconds rest.
Main set:
- 200 easy
- 2x100 fast on 1:20
- 300 easy
- 3x100 fast on 1:20
- 400 easy
- 4x100 fast on 1:20
- 500 easy
- 5x100 fast on 1:20
Keep the fast 100s tight, with only 3 to 5 seconds rest, and adjust the interval for your level. Main set total: 2,800m.
Cool-down: 200 to 300m easy.
4. Lucky Number 8
Focus: variety, pulling, and short speed. Total: about 4,800m.
Warm-up: 10 minutes easy.
Pre-set: 16x50, building pace in sets of four (4x50 easy, 4x50 moderate, 4x50 moderate to strong, 4x50 strong), with 10 seconds rest.
Main set:
- 800 pull at a moderate pace
- 8x100 on decreasing intervals: 1:40, 1:35, 1:30, 1:25, then repeat
- 4x200, building from easy on the first to race pace on the fourth, on 3:10
- 8x50, odds fast on 0:45 and evens smooth on 1:00
- 16x25, cycling easy, build, fast, fast
Main set total: 4,000m.
Cool-down: 200m easy.
How Often Should You Swim These Workouts?
For most triathletes, two to four swims a week builds endurance without burning you out. Slot one or two of these structured sets in as your key sessions, and keep the rest easy or technique-focused. In pre-season, lean into the longer endurance work, then sharpen toward race pace as your event gets closer. Build the volume gradually week over week, and let recovery weeks lower the load so your body absorbs the work.
If you want this mapped out for you rather than picking sets week to week, a structured swimming workout plan removes the guesswork. IRONMAN's training plans and the Swim Smart program lay out the progression, and newer triathletes can start with the beginner training hub.
Build Your Technique Alongside The Endurance
Fitness only pays off if your stroke is efficient. As you log these sets, keep working your form so you are not just swimming hard, you are swimming well. Use the pre-set and pull-buoy work to feel a long body line and a clean catch, and breathe on both sides to stay balanced.
If technique is your limiter, train it directly with the 6 elements of a perfect swim stroke, the 5 essential freestyle drills, and breathing right to swim better. When you are ready to take that fitness to race day, the 5 keys to open-water swimming bridge the gap from the pool to open water on the start line.
Frequently Asked Questions
How long should a swim workout be? These structured sets run about 4,000 to 4,800m, or roughly 60 to 90 minutes including warm-up and cool-down. If that is more than you can manage, shorten the main set by cutting rounds. A focused 30 to 45 minute swim with a clear main set still builds fitness.
What is the 80/20 rule in swimming? It is the idea that about 80 percent of your training should be easy or moderate and only about 20 percent hard. These workouts hold to that by pairing demanding main sets with easy recovery swims and lots of easy volume across the week, so you build endurance without constant fatigue.
How many times a week should I swim? Two to four times a week suits most triathletes building swim endurance. Use one or two of these sets as your key sessions and keep the others easy or technique-focused.
Can beginners do these workouts? Yes. Start with fewer rounds, longer rest, and an easier interval, and focus on holding good form rather than hitting the times. Build up week by week. If you are brand new to the pool, start with the beginner basics first.
Do I need a pull buoy and a snorkel? They help, but they are optional. A pull buoy lets you isolate your upper body and feel your catch, and a snorkel lets you focus on body position without turning to breathe. A good pair of goggles is the one piece of gear worth getting right.
What is a swimmer's minute? It is shorthand for an extra 30 to 60 seconds of rest between hard efforts, used to reset before the next block so you can hold quality pace.
Take the Guesswork Out of Your Swim
You have four proven workouts to build endurance. The next step is putting them inside a plan that progresses week over week toward your race. Browse IRONMAN’s training plans to build your full season around it.
Start the Swim Smart Program →Laura Siddall is a British professional triathlete based out of San Francisco. Visit her online at laurasiddall.com.