12 First Triathlon Mistakes I’d Avoid (Beginner’s Guide)

I completed my first Sprint Triathlon one month ago, in August 2023.

It wasn’t a failure — but looking back, there are so many things I could have done better.

I wrote this post to document my first triathlon mistakes and lessons, so that if you’re training for your first triathlon, you don’t have to learn everything the hard way like I did.

My First Triathlon

On a random day in May, I decided I wanted to do a triathlon.

Specifically, a Sprint Triathlon in my area.

So… I just started training.

No plan. No structure. No real understanding of swimming, cycling, or running technique.

• I didn’t know if my swim technique was correct
• I didn’t know running technique even existed
• I didn’t know saddle height or bike position mattered

I basically trained on motivation alone — which works for a while, but not forever.

The Steps To Finishing Your First Triathlon

These are the steps that I took in my training and preparation for my first Sprint Triathlon.

The things that I did, and the things I wish I did.

Mistake #1: Not Setting a Clear Goal

A goal without a plan is just a wish.

My goal was simple:
Finish my first Sprint Triathlon in under 2 hours.

That might not sound impressive, but for a first race, it was realistic and motivating.

Use the SMART framework:

• Specific: Sprint distance (750m / 20km / 5km)
• Measurable: Finish time
• Achievable: With consistent training
• Relevant: A perfect entry into triathlon
• Time-bound: A fixed race date

Once the date is set, everything else falls into place.

Mistake #2: Underestimating the Mental Side of Triathlon

At some point in every race, it gets hard.

That’s where success or failure is decided.

If you haven’t thought about your “why” before race day, you’ll struggle when things don’t go as planned.

Triathlon isn’t just about fitness — it’s about:

• Training when you don’t feel like it
• Staying calm when conditions are bad
• Not quitting when your body wants to stop

Mental strength is trained, just like endurance.

Mistake #3: Overcomplicating Gear for My First Sprint Triathlon

Do you need a tri suit?

No — but I’d recommend one.

A tri suit:

• Dries quickly after the swim
• Has light padding for the bike
• Prevents chafing during the run

Speaking of chafing: anti-chafe balm is non-negotiable.
(But never use Vaseline with a wetsuit — it damages the material.)

Wetsuit?

Only if:

• Water temperature requires it
• Or you’re uncomfortable swimming without one

Socks?

I’m 100% Team Socks.

Yes, you lose a few seconds in transition — but comfort beats speed for beginners.

Just practice putting them on quickly.

Mistake #4: Training Without Structure

You can finish a Sprint Triathlon without a plan.

But if you want to:

• Enjoy the process
• Improve faster
• Avoid injury

…some structure helps a lot.

I self-coached my first race — and learned the hard way how tricky that is.

A coach isn’t mandatory, but they:

• Fast-track your learning
• Help you avoid common mistakes
• Take the guesswork out of training

Mistake #5: Avoiding Proper Swim Technique

My freestyle was so bad I couldn’t swim more than 50m.

So I raced breaststroke.

It worked — but it wasn’t ideal.

If I could start again, I’d:

• Take a beginner freestyle course earlier
• Practice open water swimming more
• Learn sighting and breathing under pressure

Open water reality check

• You’ll get kicked
• You’ll swallow water
• You’ll feel rushed

Start slow. Let faster swimmers go first.
Panic wastes more energy than bad technique.

Mistake #6: Running Too Fast Too Often

Most beginners make the same mistake:

They run too fast, too often.

Aerobic training feels boring — but it builds your engine.

Rule of thumb:

• ~90% easy aerobic
• ~10% harder efforts

This applies to:

• Running
• Cycling
• Even swimming (to a degree)

Your base fitness determines everything else.

Mistake #7: Underestimating the Bike Split

The bike makes up about 50% of your race time.

Ironically, it was the discipline I trained the least — and performed best in.

Focus on:

• Long, easy aerobic rides first
• Then race-specific intensity later
• Bike handling and confidence

And yes — learn basic bike mechanics.
Future you will thank you.

Mistake #8: Not Doing Enough Brick Workouts

Brick workouts = bike → run.

They teach your legs to run while tired — which feels awful at first.

I did a few, and they helped massively.

Do them more frequently as race day approaches.

Mistake #9: Skipping Strength Training

You can finish without strength training.

But if you want to:

• Stay injury-free
• Improve efficiency
• Build durable strength

…it’s worth including.

Even 1–2 short sessions per week make a difference.

Mistake #10: Not Practicing Race Nutrition

Big mistake I made:
My first gel was on race day.

Practice everything:

• Gels
• Drinks
• Timing

The bike is the easiest place to fuel — use it.

Post-race, eat whatever you can tolerate.
You’ve earned it.

Mistake #11: Ignoring Rest and Recovery

Triathletes love doing more.

Progress comes from:
Training stress + recovery

Take rest days seriously.

That’s where adaptation happens.

Do you want to become a better Triathlete?

Get the ONE Triathlon Training Recovery Guide Endurance Athletes Need!

Get the guide!

Mistake #12: Poor Taper Before Race Day

2–3 weeks before the race:

• Reduce volume by 30–50%
• Keep short race-pace efforts
• Avoid “panic training”

You won’t gain fitness — only fatigue.

Race Day: What Actually Matters

• Arrive early
• Have a checklist
• Stay calm
• Control your pace

To be honest, my first triathlon wasn’t a lot of fun.

It was cold, it was raining, I got my period.

The conditions were far from perfect. But I trained for it, so there was no way that I would have quit on myself.

You are doing this for you, not for anybody else, so show yourself what you are capable of!

Crossing the finish line changes how you see yourself.

Final Thoughts

Your first triathlon doesn’t need to be perfect.

It just needs to be finished.

You’ll learn more from one race than from months of overthinking.

And once you’ve done one — you’ll never see endurance sports the same way again.

Frequently Asked Questions

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