IRONMAN 70.3 · Los Cabos · 11 Apr 2027
How to train for IRONMAN 70.3 Los Cabos
The organiser describes this course in three words: ocean, rolling, flat. Most people read the middle one as scenery, a bit of up and down in a place the organiser sells on Land's End and its beaches. The file reads it differently. Over 90.5 km the road climbs 827 m, and it never does it in one place. It does it in 25 rises of 3 percent or steeper, with 28 descents to hand the height back.
So Los Cabos is not a hilly course. It is a course that keeps changing its mind, for 3:10:00 if you ride it as a Trained athlete, and then gives you a flat 21.1 km to find out what all that changing cost.
By Kian Briel, founder. Analysed by engine 1, updated
What is actually on the road
The organiser's own course files, drawn the way the Event Analyzer draws a member's race.
- Swim1.91 km0 m upCourse file
- Bike90.5 km827 m upCourse file
- Run21.1 km101 m upCourse file
The swim is 1.9 km in the ocean. Los Cabos sits where the desert meets the sea, and where the Pacific Ocean meets the Sea of Cortez. The organiser lists no water temperature for any of its last three editions.
The bike opens with a climb. The first 704 m rise at 4.3 percent, and at 1.3 km comes the steepest sustained climb of the day, 600 m at 5.7 percent. From there the profile is a saw. Short rises of 3 to 5.7 percent, most of them followed closely by a drop, the steepest a 611 m descent at 6.1 percent at kilometre 38. The engine cuts the leg into 103 segments. The longest flat stretch is about 6 km, and the one that holds the most time takes only 6.3 percent of the bike leg.
The run is 21.1 km with 101 m of climbing. After a gentle drop over the first 452 m, the engine reads the rest as one flat segment, 98 percent of the run leg.
Put together, 928 m of climbing across the day and 82.2 percent of the course flat by distance. That share undersells it. Every metre of the 9.6 km of climbing and the 10.6 km of descending sits on the bike.
Course shape by distance
- Flat 82%
- Climbing 9%
- Descending 9%
The longest stretches
- Bike, climbing0.6 km2% of the bike
- Bike, flat6 km6% of the bike
- Run, flat20.7 km98% of the run
Each row is one unbroken stretch of the course that keeps the same shape the whole way. The number is how much of that leg you spend inside it, and it comes out the same whether you are fast or slow.
What this course asks of each leg
Twelve training dimensions scored for each leg against its own course, the way the Event Analyzer scores a member's race.
Muscular endurance on the bike, and the discipline to keep it steady while the road will not. The demand model scores aerobic endurance at 85 and muscular endurance at 82 for the bike leg, with threshold capacity at 70 and threshold durability at 69 close behind. The bike fills 53 percent of a Trained athlete's day, so the eight largest demands on the course are all bike demands. The run's pair reads 85 and 81. The swim's reads 85 and 80.
The score that describes Los Cabos best sits lower down. High-intensity capacity reads 58 on the bike against 40 on the run and 40 in the water. Strength and force read 46 on the bike and 30 on the run. That gap is the saw. No single rise is long, and the steepest sustained one is 1.8 percent of the bike leg. But there are 25 of them, and each asks for a short spell above your steady number before the descent gives it back. Ask the engine for a session from this file and it returns a dozen 45-second efforts above threshold, each followed by five minutes of soft pedalling. That is the rhythm of the leg, compressed.
The bands put numbers on it. A Trained athlete swims 38:22, rides 3:10:00 at 182 W and runs 1:59:40, for 5:58:02. The Competitive band finishes in 5:12:57 from 4.15 W/kg at 75 kg, about 22 minutes quicker on the bike and 18 on the run. It gets there by holding 249 W over the rises as well as between them, and by still having a run afterwards.
Heat belongs in the picture. The organiser logged highs of 27 C in 2026 and 30 C in 2025, and environmental resilience scores 60 on every leg. For a Trained athlete the run starts close to four hours after the gun, on a flat road with nothing to break the effort.
- Aerobic endurance85
- Muscular endurance80
- Threshold capacity70
- Aerobic durability65
- Technical skill65
- Threshold durability65
- Environmental resilience60
- Fueling resilience55
- High-intensity capacity40
- Anaerobic capacity25
- Strength / force20
- Sprint power5
Nymiva reads what you can already show, from your own data
Connect your training history and the Focus Lab scores the same twelve dimensions this course demands against where you sit today. The gap between the two is what you train.
- MeasuredFrom your thresholds and testsThreshold power, threshold pace, critical swim speed and field tests you have done. The dimensions they can carry are scored directly.
- EstimatedFrom your training historyConnected activities are read for what they prove: long efforts, late-session fade, repeated hard work, fueling on long days. Each score says how it was read.
- ProxyFrom a stand-in, and named as oneWhere only an indirect signal exists, the score carries the proxy it came from and a lower confidence, never a number dressed as a measurement.
- UnmeasuredHonestly blankA dimension nothing in your data can answer stays unmeasured. It is never a zero, and the plan does not pretend to know it.
Every dimension ends in one word
- Develop the course asks more than you can show
- Maintain close enough to hold at the minimum dose
- Covered nothing to build here
- Unmeasured the course needs it, your data cannot say yet
Nymiva scores a member on the same twelve dimensions it used for the course above, reading them from thresholds and connected training history, and records the evidence behind each number. A gap is counted only where the course asks for more than the member can show, and it is weighted by the share of the day it fills. At Los Cabos the bike is over half the day and the swim about a tenth, so a bike gap weighs roughly five times a swim gap of the same size.
This page has no member behind it. Its season stands in with the plainest assumption, that the gaps fall where the demands are largest, and lays out 24 weeks in 5 developmental blocks before a two-week taper. Aerobic endurance leads the first and the last block in all three sports. In the second, threshold durability leads on the bike while aerobic durability leads the run and the swim. Threshold capacity leads everywhere in the third, and muscular endurance in the fourth. A member's season starts from their own numbers and will depart from this one.
Train the bike to protect the run
Which demands matter most across the whole race. A leg's demand counts for as much of the day as that leg takes, so a score of 85 on the bike outweighs the same score on the swim.
- 01Aerobic enduranceBike leg, 53% of the day85 × 53%45
- 02Muscular enduranceBike leg, 53% of the day82 × 53%44
- 03Threshold capacityBike leg, 53% of the day70 × 53%37
The bike takes 53% of the Trained reference band’s day, so its demands carry the most race weight. What the bike leaves in the legs is what the run gets.
Which demand gets a block, and when
The engine freezes one lead focus per sport on every developmental block, holds the rest at maintenance, and verifies before it reprioritises.
An illustration, not your plan. This page has none of your data, so the season below is the engine’s answer to one stated assumption: that your gaps line up with what IRONMAN 70.3 Los Cabos demands. Your own season is built from your history, your thresholds, the days you can train and the races you have entered, and it will differ from this in its priorities, its sessions and its load.
- 01Run muscular endurance, a practice block4 weeks
- 02Run aerobic endurance, a development block4 weeks
- 03Bike muscular endurance, a practice block4 weeks
- 04Bike aerobic endurance, a development block4 weeks
In the order the allocator places them, general first, most race-like last.
- Week 1PrepPrep
A lead-in week. It develops nothing by design.
- Weeks 2 to 5Foundation 1Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportBike threshold durability
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportRun aerobic durability
- SupportSwim aerobic durability
- Weeks 6 to 9Foundation 2Closes with a recovery week
- PriorityBike threshold durability
- PriorityRun aerobic durability
- PrioritySwim aerobic durability
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- Weeks 10 to 13Foundation 3Closes with a recovery week
- PriorityBike threshold capacity
- PriorityRun threshold capacity
- PrioritySwim threshold capacity
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold durability
- SupportRun aerobic durability
- SupportSwim aerobic durability
- Weeks 14 to 17Event shaping 1Closes with a recovery week
- PriorityBike muscular endurance
- PriorityRun muscular endurance
- PrioritySwim muscular endurance
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike threshold capacity
- SupportBike threshold durability
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportRun aerobic durability
- SupportSwim aerobic durability
- Weeks 18 to 21Event shaping 2Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportBike threshold durability
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportRun aerobic durability
- SupportSwim aerobic durability
- Weeks 22 to 23PeakPeak
The taper. Load comes down toward the race, content stays specific.
- Week 24RaceRace
Race week.
Held at maintenance between blocks
- Runmuscular endurance, aerobic endurance, aerobic durability, threshold capacity, threshold durability
- Bikemuscular endurance, aerobic endurance, aerobic durability, threshold capacity, threshold durability
- Swimaerobic endurance, aerobic durability, threshold capacity, threshold durability, muscular endurance, technical skill
Touches scheduled by each capability’s own decay, at a fraction of its development dose, so earlier work is still there on race day.
The sessions the blocks are built from
One entry per kind of work the block trains, at the intensity that work is meant to be done at. Where the same work runs at several lengths, the entry shows the span it grows across rather than one entry per length.
- Foundation 1 · Weeks 2 to 575 to 240 min
150 to 210 min at Zone 2
BikePower, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 540 to 270 min
180 to 210 min at Zone 3, then 30 min at Zone 4
BikePower, Zone 3Trains aerobic capacity - Foundation 1 · Weeks 2 to 535 to 120 min
90 min at Zone 2
RunPace, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 550 min
4 x 1.5 min at Zone 3, 6 min easy between
RunHeart rate, Zone 3Trains aerobic capacity - Foundation 1 · Weeks 2 to 545 to 51 min
4 x 8 min at Zone 2, 1 min easy between
SwimPace, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 547 to 81 min
3 x 1000 m at Zone 3, 0.3 min easy between
SwimPace, Zone 3Trains aerobic capacity
12× rolling-course surges
0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, then 0.8 min at Zone 5, 5 min easy between
Compiled by the deterministic course compiler from the organiser’s file: the course’s one repeatable requirement, rehearsed at a dose the progression allows.
- Bike
- 89 min
- Trains threshold durability
- Supports muscular endurance
- Supports high intensity capacity
24 weeks, laid out backwards from race day
The shortest runway Nymiva builds for this event type, with its blocks, recovery weeks, taper and race week in place.
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- Prep
- Foundation
- Event shaping
- Peak
- Race
- Recovery week
Your own season carries these same phases on your own dates, with the load solved from your fitness and the days you can train, and it changes when your data does.
What each level does on the day
Reference finish times per peer band, the pacing plan the model holds each band to, and where the day is decided.
| Band | Swim | Bike | Run | Finish |
|---|---|---|---|---|
| Recreational2:11 /100m critical swim speed · 2.47 W/kg at 75 kg · 6:08 /km threshold pace | 0:45:17 | 3:29:52 | 2:23:55 | 6:49:04 |
| Trained1:51 /100m critical swim speed · 3.03 W/kg at 75 kg · 5:06 /km threshold pace | 0:38:22 | 3:10:00 | 1:59:40 | 5:58:02 |
| Competitive1:36 /100m critical swim speed · 4.15 W/kg at 75 kg · 4:20 /km threshold pace | 0:33:11 | 2:48:05 | 1:41:41 | 5:12:57 |
| Elite1:26 /100m critical swim speed · 5.27 W/kg at 75 kg · 3:50 /km threshold pace | 0:29:44 | 2:33:30 | 1:29:57 | 4:43:11 |
Pacing plan
- 0 km4.3%14.4 km/h2:56
- 0.7 km1.2%25.1 km/h0:23
- 0.87 km-3.5%47.6 km/h0:20
- 1.12 km0.5%28.4 km/h0:27
- 1.33 km5.7%11.7 km/h3:05
- 1.93 km-0.5%33.3 km/h0:23
- 2.15 km-5.2%54.9 km/h0:41
- 2.78 km0.9%26.5 km/h1:35
95 more segments in the full plan.
- Run: reach 4:20 /km and this course gives back 45:05.
Where it is decided
In the first two kilometres of the bike, and then two dozen more times.
The steepest sustained climb on the course arrives 1.3 km after you mount, on legs fresh out of the ocean. It is short, it is right there, and going hard up it feels like the natural thing to do. It sets the tone for the whole leg. A rider who answers it with a surge will answer the next 24 the same way.
Each rise is cheap on its own. Together they are the leg. The descent after each one hands the effort back as free speed, and that is what makes the pattern so easy to slip into. Surge, freewheel, surge, freewheel, and an average that still reads 182 W while the legs have ridden something much harder.
Then the flat run, and a flat run is an honest judge. The engine reads almost all of it as one segment. A Trained athlete covers it in 1:59:40 from an input of 5:06 /km threshold pace, the Competitive band in 1:41:41. Whether you run your band's number or walk parts of it was settled back on the rises.
Getting it wrong
Training for a rolling course on flat roads is the first mistake. Long steady rides build the aerobic base this course needs, but they never teach you to hold one number while the gradient changes every few hundred metres. That skill has to be practised on terrain that asks for it.
The second is the opening climb. A 5.7 percent ramp at 1.3 km, straight out of the water, is the worst possible place to find out how your legs feel. Ride it at the number you plan to hold at kilometre 60.
The third is the heat. The highs over three editions ran from 27 C to 30 C, and a Trained athlete starts the run nearly four hours in. A flat road gives no reason to slow down, so the pace has to come from the conditions rather than from the number in your head. Start the run slower than it feels you should.
Conditions on the day
- 2026high 27 C, low 21 C
- 2025high 30 C, low 20 C
- 2024high 27 C, low 14 C
From the organiser’s own records. Not a forecast.
Every session is a claim, every block is a test
A plan is not a calendar. Each key session states what it trains and how that is checked, and each block ends with a public verdict before the next one is chosen.
What a block promises
Bike aerobic endurance moves from your baseline to a stated target by the end of Foundation 1
- The baseline is your measured score when the block starts. The target is the score the model predicts for it.
- Verified at the block’s recovery week, by a field test or a refresh of the supply read from your history.
- Confidence rises by agreement between independent signals, never by one metric crossing a line.
- A block that misses its target is a public miss. The next block is chosen from what was proven, not from what was planned.
- 01Stimulus achievedThe work landed in the zone the session named, for the dose it named.
- 02Partially achievedSome of the work landed. The session banks what it can prove.
- 03Not achievedThe load may have been there. The stimulus was not, so nothing is banked.
- 04Data insufficientNo usable stream. The session is neither credited nor blamed.
- Session verified
- Progression banked
- Block verified
- Priority reassessed
- Plan adapted
Your numbers, this course
Analyze IRONMAN 70.3 Los Cabos against my fitness
The same simulation and the same Focus Lab read, on your thresholds instead of a band’s. Three numbers give a finish estimate and a partial read. A connected history gives the whole table.
The first 14 days are free.
- Trained band finish
- 5:58:02
- Of the day on the bike
- 53%
- Dimensions scored per leg
- 12
- Season runway shown
- 24 wk
Questions people ask
- How hilly is the IRONMAN 70.3 Los Cabos bike course?
- The organiser calls it rolling, and the file agrees. It climbs 827 m over 90.5 km in 25 rises of 3 percent or steeper, with 28 descents to match. The steepest sustained climb is 600 m at 5.7 percent, 1.3 km into the bike, and no flat stretch runs longer than about 6 km.
- Is the IRONMAN 70.3 Los Cabos run flat?
- Yes. The run climbs 101 m over 21.1 km. After a gentle drop in the first 452 m, the engine reads the rest as one flat segment holding 98 percent of the run leg.
- How hot is IRONMAN 70.3 Los Cabos?
- The organiser logged highs of 27 C in 2026, 30 C in 2025 and 27 C in 2024, with lows between 14 C and 21 C. It lists no water temperature for any of those editions, so check the swim conditions in race week.
- How long is the season on this page?
- The illustrative season runs 24 weeks, with five developmental blocks and a two-week taper. It is built from the course alone. A member's season starts from their own numbers and can be longer.
Course data from the organiser’s published files, analysed 24 Sept 2026 by engine 1, demand model 4. Reference times are simulated for a peer band at a stated reference athlete and are not a prediction for anyone. Nothing on this page is medical advice.
IRONMAN® and IRONMAN 70.3® are registered trademarks, and 5150 is a trademark, of World Triathlon Corporation. Nymiva is an independent training platform and is not affiliated with, sponsored by or endorsed by World Triathlon Corporation. Course data is read from the organiser’s public course pages for the purpose of describing the event.