Search
shop

How to improve your half Ironman swim time – tips for swimming faster over 1.9km distance

Get tips, advice and example swim workouts to help you improve your half Ironman swim split from a top level swim coach.
Content Director
Last updated -

The 1.9km swim at the start of a half Ironman/middle distance triathlon hits that tricky not-so-sweet spot. It’s long enough that you need a solid base of endurance. But short enough that, if you want to be coming out with the front pack in your age group, you need to be able to hold speed. And getting the balance right in training to see improvements can be difficult to master.

Expert swim coach Lucas David, a National Champion swimmer himself who works with everyone from elite level swimmers and triathletes to age-groupers, gives us his top tips for improving your speed and your endurance in the water.

meet THE EXPERT
Lucas David swim coach
Lucas David
Lucas is a national champion swimmer turned swimming coach, helping world champions and pro triathletes reach peak performance. Follow him on Instagram for more swim tips and to find out how he can help take your swimming to the next level.

Training focus for half Ironman swim speed: get fast, then train yourself to hold pace

With pool time limited, and public lane sessions often being chaotic at best. It can be easy to fall into the trap of swim training without any specificity. Many age-group triathletes make the mistake of either only ever swimming easy (which is great for endurance, but won’t help you get faster). Or conversely, hopping in the water and smashing out a set of fast 25s and 50s because – let’s face it – that’s way more fun than ploughing up and down in the lane. Which will give you a good bit of short distance pace, but won’t help you when you’re exhausted before you even hit the first turn buoy on race day.

Like the bike and run training for a half distance triathlon, you’ve got to get that balance of speed and endurance nailed for optimal performance. “If you want to get quicker over the 1.9km swim distance, you need to cycle between threshold work and building your endurance engine,” says Coach Lucas. “It’s great to be in shape. But let’s say you want to hold 1:30/100m pace on race day, but you’ve never swum quicker than 1:35/100. Hitting that target race pace is going to be incredibly difficult!”

“Start with threshold work to get fast first, and then train yourself to hold that pace over longer distances.”

Example swim workout to boost your half Ironman swim speed

Below you’ll find an example swim set from Lucas which is tough, but an ideal way to get your body to tolerate holding a higher swim pace for longer.

threshold boosting swim set

Note from Coach Lucas: This is a VERY hard set so you can do less rounds if you are a beginner but over time you want that threshold to be right around your 1.9k pace.

Main Set (2000) 

10 x 200s 

Odds – Done at threshold (PB + 24) @ 30 rest 

Evens – Done as MAX! @ 1 minute rest 

Make sure your open water swim training has structure and purpose

Plenty of us are guilty of ticking off a full winter of structured pool swim sets. Only to get in open water and swim aimlessly around at the same easy pace. Which is fun – but isn’t necessarily the best approach if you want to be able to swim fast on race day!

This is why, Lucas says, it’s important to approach your open water swimming sessions with the same focus, structure and purpose that you take to the pool. “How you train is how you race. Anyone can do volume, but open water time is often rare and incredibly valuable. So we need to be as race specific as possible!”

Stay tuned for more swimming tips

In the coming months we’ll be bringing you more swim content, including pool and open water swim sets – so stay tuned. Sign up below to be kept in the loop…

Jenny Lucas-Hill
Written by
Jenny Lucas-Hill
Jenny Lucas-Hill is Content Director at TRI247. A five-time Ironman finisher, she's also a qualified personal trainer and sports massage therapist.
Discover more
Challenge The Championship Marjolaine Pieree
How to qualify for Challenge The Championship – and why it should be on your triathlon bucket list
Cadomotus aero triathlon cycling shoes
Can your triathlon cycling shoes make you faster? How shoe choice could speed up your triathlon finish times
French Riviera T100 bike course Esterel
Is this the ultimate middle distance triathlon bike course? We rode the French Riviera T100 bike course and it’s EPIC
Ironman gear guide – everything you need to get to the finish line of a full distance triathlon
Challenge St. Pölten 2024 - image credit Jose Luis Hourcade / Challenge Family
Expert swim coach on the three most common swim mistakes age group triathletes make (and how to fix them!)
latest News
Jonny Brownlee Tokyo 2020 Mixed Team Relay run leg
Triathlon superstar Jonny Brownlee has revealed why he will NOT be doing an IRONMAN any time soon
Sam Long St George 2024 photo credit Getty Images for IRONMAN
IRONMAN 70.3 Chattanooga results 2025: Long and Alexander win as swims are CANCELLED
Hanne De Vet wins Challenge Family The Championship 2025
The Championship 2025 women’s results: Hanne De Vet star of the show in Samorin
kristian hogenhaug wins challenge family the championship 2025
The Championship 2025 men’s results: Høgenhaug back to winning ways in Samorin
Kristian Blummenfelt wins 703 Aix en Provence 2025
IRONMAN 70.3 Aix-en-Provence results 2025: Blummenfelt and Pierré just too good
triathlon on your terms
Never miss out with our triathlon alerts & digest. Get a dose of adventure & inspiration with Boundless.
The 247 Group

The home of endurance sports

Share to...