IRONMAN 70.3 · Phu Quoc · 15 Nov 2026
How to train for IRONMAN 70.3 Phu Quoc
Flat and fast is how the organiser sells IRONMAN 70.3 Phu Quoc, and on paper it is about as flat as a half-distance triathlon gets. The bike climbs 98 m. Of the 115 km you cover, 99.8 percent reads as flat. First-timers come here for a personal best and plan a race about pacing on level road.
The course is not what decides it. The weather is. The organiser logged highs of 32 C and 31 C and water at 29 C three editions running, and the demand model puts environmental resilience at the very top of the whole course, above aerobic endurance, on every leg.
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 km5 m upCourse file
- Bike91.9 km98 m upCourse file
- Run21.1 km23 m upCourse file
At Three Coconut Tree Beach you start in the sea, 1.9 km on a triangle course with a rolling start. The organiser calls the water crystal-clear. It is also warm, 29 C in 2025.
The bike runs 91.9 km along the southern coastline of Phu Quoc Island, with the Gulf of Thailand beside you, and crosses through Sun World Hon Thom. The organiser singles out a 15 km straightaway with no sharp turns. The file agrees with every word of "flat". It holds one descent of 153 m and nothing else that changes grade: an 81.2 km stretch before it, a 10.6 km stretch after it, and 98 m of climbing spread so thin that the engine never finds a climb.
The run is two loops out and back along the beachfront, 21.1 km with 23 m of climbing, and the engine reads it as a single flat segment. It starts and finishes at Phu Quoc Marina, where the organiser says spectators line the final stretch.
Course shape by distance
- Flat 100%
- Climbing 0%
- Descending 0%
The longest stretches
- Bike, flat81.2 km89% of the bike
- Bike, flat10.6 km12% of the bike
- Run, flat21.1 km100% 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.
Environmental resilience scores 90 on the swim, the bike and the run, the highest single score on the page. Then comes the usual half-distance pair, aerobic endurance at 85 and muscular endurance at 80 or 81. Threshold capacity follows at 70, with both kinds of durability at 65.
The ordering matters because it tells you what a good day here looks like. Terrain asks nothing: high-intensity capacity reads 40 on the bike and strength and force 35. There is no hill to hide in and no descent to recover on. Heat, meanwhile, asks from the first stroke in 29 C water to the last kilometre on the beachfront, and it asks more the longer you are out.
That is where the bands come in. A Trained athlete swims 38:22, rides 2:58:45 at 182 W and runs 1:59:38, a day of 5:46:45. The run fills 35 percent of it and begins close to four hours after the start, with the heat of the whole day already behind you. The Competitive band covers the same course in 5:02:57, riding 2:38:07 from 4.15 W/kg at 75 kg. It is out in the heat for less time, and that is part of why it is faster.
Fueling resilience scores 55 on the bike and the run. On a course this hot and this long for most of the field, the ability to keep taking on food and drink late in the day is a real demand, not an afterthought.
- Environmental resilience90
- Aerobic endurance85
- Muscular endurance81
- Technical skill70
- Threshold capacity70
- Aerobic durability65
- Threshold durability65
- 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
The course and the athlete are scored on the same twelve dimensions in Nymiva: the course from its file and its declared environment, the athlete from thresholds and connected training history, each score with a note on its source and its confidence. A gap is only a gap where the course asks for more than the athlete can show, and it is weighted by the share of the day it covers.
With no reader data here, the season below takes the simplest reading, that your gaps line up with the demands, and lays out 24 weeks in 5 developmental blocks before a two-week taper. Aerobic endurance leads the first block everywhere. The swim then moves to threshold capacity and technical skill while the bike and run build aerobic durability and threshold capacity. Muscular endurance leads the fourth block and aerobic endurance the fifth. A member's season starts from their own numbers and will not match 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.
- 01Environmental resilienceBike leg, 52% of the day90 × 52%46
- 02Aerobic enduranceBike leg, 52% of the day85 × 52%44
- 03Muscular enduranceBike leg, 52% of the day80 × 52%41
The bike takes 52% 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 Phu Quoc 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
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun aerobic durability
- Weeks 6 to 9Foundation 2Closes with a recovery week
- PrioritySwim threshold capacity
- PriorityBike aerobic durability
- PriorityRun 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 technical skill
- Weeks 10 to 13Foundation 3Closes with a recovery week
- PriorityBike threshold capacity
- PriorityRun threshold capacity
- PrioritySwim technical skill
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportSwim threshold capacity
- SupportBike aerobic durability
- SupportRun 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
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun 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
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun 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
Sustained course race pressure
60 min at Zone 4
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
- 85 min
- Trains threshold durability
- Supports aerobic durability
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 | 3:14:01 | 2:23:52 | 6:33:10 |
| Trained1:51 /100m critical swim speed · 3.03 W/kg at 75 kg · 5:06 /km threshold pace | 0:38:22 | 2:58:45 | 1:59:38 | 5:46:45 |
| Competitive1:36 /100m critical swim speed · 4.15 W/kg at 75 kg · 4:20 /km threshold pace | 0:33:11 | 2:38:07 | 1:41:39 | 5:02:57 |
| Elite1:26 /100m critical swim speed · 5.27 W/kg at 75 kg · 3:50 /km threshold pace | 0:29:44 | 2:24:24 | 1:29:55 | 4:34:03 |
Pacing plan
- 0 km0%30.8 km/h2:38:09
- 81.2 km-3.9%49.4 km/h0:11
- 81.3 km0%30.8 km/h20:35
- Run: reach 4:20 /km and this course gives back 43:48.
Where it is decided
In the first 81.2 km of the bike, where nothing seems to be happening.
That single stretch is 88.5 percent of the bike leg, and the engine finds no feature in it worth splitting out. Nothing tells you to ease off. No climb raises your heart rate as a warning, no descent hands you a rest, and the straightaway invites a number you trained for in cooler air. When the engine turns this bike into a workout, it asks for an hour of Zone 4 held steady, with no surges in it. That is an honest summary of the leg. The effort never changes. The question is only what level you can hold in 32 C and still run afterwards.
The answer arrives on the beachfront. The run is flat, two loops, crowded, and it starts after three hours of riding in the heat. Riders who held 182 W with heat in mind start it with something left. Riders who held the number from their cool training days find out on the second loop.
Getting it wrong
The first mistake is treating a flat course as a pacing problem only. Pacing on level road is easy to measure and easy to hold. The heat changes what a sustainable number is, and the longer you are out, the lower that number sits. Planning the bike from spring power and ignoring the thermometer is how a fast course turns slow.
The second is the swim. Water at 29 C feels welcome at the start, and the rolling start and the triangle let you settle. It also means you begin the bike already warm. There is no cool first hour on this course.
The third is the run's second loop. The first loop out and back along the beachfront feels fine, the coastal breezes help, and the crowd near Phu Quoc Marina lifts the pace. The second loop comes after more time in the heat, and there is no terrain left to blame. Run the first loop at the pace the second one can afford.
Conditions on the day
- 2025high 31 C, low 26 Cwater 29 C
- 2024high 32 C, low 26 Cwater 29 C
- 2023high 32 C, low 26 Cwater 29 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 Phu Quoc 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
- 5:46:45
- Of the day on the bike
- 52%
- Dimensions scored per leg
- 12
- Season runway shown
- 24 wk
Questions people ask
- Is the IRONMAN 70.3 Phu Quoc course flat?
- Yes, as flat as a half-distance triathlon gets. The bike climbs 98 m across 91.9 km and 99.8 percent of the whole course reads as flat by distance. The organiser describes a 15 km straightaway with no sharp turns along the southern coastline.
- How hot is IRONMAN 70.3 Phu Quoc?
- The organiser logged highs of 31 C in 2025 and 32 C in 2024 and 2023, with lows of 26 C each year. The water was 29 C in all three editions. Heat is the strongest demand on the course.
- Where is the swim at IRONMAN 70.3 Phu Quoc?
- At Three Coconut Tree Beach, 1.9 km on a triangle course with a rolling start, in water the organiser logged at 29 C. The wetsuit decision is not on the course page, so check it 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 own season starts from their numbers.
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.