IRONMAN · Tallinn · 7 Aug 2027
How to train for IRONMAN Tallinn
Estonia sells this one on speed, and the sales pitch is accurate. Of the 225 km you race here, 98.2 percent reads as flat, and the whole day climbs 704 m. Athletes see those numbers and hear permission.
What they mean is that nothing on this course will slow you down on your behalf. A hilly race makes some of your pacing decisions for you. Tallinn makes none of them. The engine finds two rises in 179 km of riding, lasting 102 and 150 seconds for a Trained rider, and after that it is road you can ride as hard as you like, right up to the moment outside Unibet Arena when you get off and start four laps on foot.
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.
- Swim3.8 km5 m upCourse file
- Bike179 km482 m upCourse file
- Run42.2 km217 m upCourse file
The swim is one loop of Lake Raku, 3.8 km in a venue the organiser describes as clear water over a sandy lakebed, average depth 6.4 m and maximum depth 18.7 m. From swim exit to Transition 1 on Karuse and Sinirebase streets is about 300 m on foot.
Out of Lake Raku the bike takes city roads and countryside south of Tallinn, away to the southern villages and back towards the turn-around near Unibet Arena, which you reach three times before the third pass sends you to Transition 2. The organiser's page states no distance for the leg. Its GPX file measures 179 km and 482 m of climbing. Two of those rises are big enough for the engine to name, 404 m at 3.7 percent at kilometre 50 and 640 m at 3.3 percent at kilometre 116. There are 8 aid stations out there and a Personal Need station you pass twice.
Then four laps between Rocca al Mare and Stroomi Beach along Tallinn Bay, 42.2 km for 217 m, finishing in front of Unibet Arena. The steepest thing the engine reads on the run is 188 m at 5.9 percent, arriving at kilometre 7.4, and it comes round again with the laps.
Course shape by distance
- Flat 98%
- Climbing 1%
- Descending 1%
The longest stretches
- Bike, flat56.6 km31% of the bike
- Bike, flat62.3 km34% of the bike
- Run, climbing0.19 km1% 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.
Aerobic endurance first, aerobic durability next, muscular endurance a shade behind, and the scores barely move from leg to leg. The demand model reads aerobic endurance at 95 on all three sports. Aerobic durability reads 91 on the bike and 95 on the run. Muscular endurance reads 91 on both. Under them sit fueling resilience at 85 and threshold durability at 81. High-intensity capacity reads 28 on the bike and 30 on the run, anaerobic capacity reads 15, and sprint power reads 10 on the bike and zero on the swim. The course has no use for a fifth gear. The one score that stands out anywhere is technical skill on the swim at 74, the highest that dimension reaches on this course.
Because the bike swallows more than half of a Trained athlete's day, all five of the top cross-leg demands are bike demands. Aerobic endurance and aerobic durability on the run both score 95, higher than anything the bike asks, and they still rank sixth and seventh once the ranking weights them by time.
The bands put numbers on it. A Trained athlete swims 1:19:49, rides 6:12:03 at 159 W and runs 4:16:44 for 11:58:36. The Competitive band finishes in 10:25:45, and that gap is not built on the climbs, because there are no climbs to build it on. It is 218 W instead of 159 W, held for the whole leg, and a run off it of 3:38:08 instead of 4:16:44.
Heat is rarely the story. The organiser logs a high of 21 C in 2025 and 22 C in 2024. Wind is the story, and the organiser says so itself, calling the course fast and flat and then adding the parenthesis about the wind playing a trick on you. Nymiva reads elevation out of the file and scores environmental resilience at 20 with low confidence, which is the engine admitting that a GPX track cannot see weather.
- Aerobic endurance95
- Aerobic durability90
- Muscular endurance90
- Fueling resilience85
- Threshold durability80
- Technical skill74
- Threshold capacity55
- High-intensity capacity25
- Strength / force25
- Environmental resilience20
- Anaerobic capacity15
- Sprint power0
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
Start from the gap. Nymiva scores those same twelve dimensions on the athlete side as well, from your thresholds and your connected history, with a note on each score saying how it was read and how far to trust it. A dimension is a gap only where the course asks for more than you can show. The gaps are then ranked by how much of the day they fill, which is why an identical shortfall scores almost five times heavier on the bike here than it does on the swim.
No athlete stands behind this page, so the season below cannot know your gaps. It takes the simple assumption instead, that they sit where the demands are largest, and lays out 28 weeks in 5 developmental blocks. Aerobic endurance leads the first one across all three sports. Fueling resilience leads the second, which on a day this long is a training subject rather than a race-morning decision. Durability and muscular endurance lead the two after that, and the last developmental block comes back to aerobic endurance before the taper. A member's season is built from their own numbers, and where it departs from this one is where the product is doing its job.
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, 52% of the day95 × 52%49
- 02Aerobic durabilityBike leg, 52% of the day91 × 52%47
- 03Muscular enduranceBike leg, 52% of the day91 × 52%47
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 Tallinn 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 aerobic endurance, a development block4 weeks
- 02Bike aerobic durability, a practice block6 weeks
- 03Bike muscular endurance, a practice block4 weeks
- 04Bike aerobic endurance, a development block5 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 9Foundation 1Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportRun aerobic durability
- SupportBike aerobic durability
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim aerobic durability
- SupportSwim muscular endurance
- SupportBike fueling resilience
- SupportRun fueling resilience
- SupportSwim fueling resilience
- Weeks 10 to 13Foundation 2Closes with a recovery week
- PriorityBike fueling resilience
- PriorityRun fueling resilience
- PrioritySwim fueling resilience
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportRun aerobic durability
- SupportSwim aerobic endurance
- SupportBike aerobic durability
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim aerobic durability
- SupportSwim muscular endurance
- Weeks 14 to 17Foundation 3Closes with a recovery week
- PriorityBike aerobic durability
- PriorityRun muscular endurance
- PrioritySwim aerobic durability
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportRun aerobic durability
- SupportSwim aerobic endurance
- SupportBike muscular endurance
- SupportSwim muscular endurance
- SupportBike fueling resilience
- SupportRun fueling resilience
- SupportSwim fueling resilience
- Weeks 18 to 21Event shaping 1Closes with a recovery week
- PriorityRun aerobic durability
- PriorityBike muscular endurance
- PrioritySwim muscular endurance
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike aerobic durability
- SupportRun muscular endurance
- SupportSwim aerobic durability
- SupportBike fueling resilience
- SupportRun fueling resilience
- SupportSwim fueling resilience
- Weeks 22 to 25Event shaping 2Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportRun aerobic durability
- SupportBike aerobic durability
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim aerobic durability
- SupportSwim muscular endurance
- SupportBike fueling resilience
- SupportRun fueling resilience
- SupportSwim fueling resilience
- Weeks 26 to 27PeakPeak
The taper. Load comes down toward the race, content stays specific.
- Week 28RaceRace
Race week.
Held at maintenance between blocks
- Runaerobic endurance, aerobic durability, threshold durability, muscular endurance, fueling resilience
- Bikeaerobic durability, muscular endurance, aerobic endurance, threshold durability, fueling resilience
- Swimaerobic endurance, aerobic durability, threshold durability, muscular endurance, technical skill, fueling resilience
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 975 to 240 min
150 to 210 min at Zone 2
BikePower, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 940 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 935 to 120 min
90 min at Zone 2
RunPace, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 950 min
4 x 1.5 min at Zone 3, 6 min easy between
RunHeart rate, Zone 3Trains aerobic capacity - Foundation 1 · Weeks 2 to 945 to 51 min
4 x 8 min at Zone 2, 1 min easy between
SwimPace, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 947 to 81 min
3 x 1000 m at Zone 3, 0.3 min easy between
SwimPace, Zone 3Trains aerobic capacity
2× course-matched climbs
1.3 min at Zone 5, then 1.3 min at Zone 5, 131.8 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
- 159 min
- Trains high intensity capacity
- Supports strength force
- Supports muscular endurance
28 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.
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- 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 | 1:34:12 | 6:44:21 | 5:08:45 | 13:37:18 |
| Trained1:51 /100m critical swim speed · 3.03 W/kg at 75 kg · 5:06 /km threshold pace | 1:19:49 | 6:12:03 | 4:16:44 | 11:58:36 |
| Competitive1:36 /100m critical swim speed · 4.15 W/kg at 75 kg · 4:20 /km threshold pace | 1:09:02 | 5:28:35 | 3:38:08 | 10:25:45 |
| Elite1:26 /100m critical swim speed · 5.27 W/kg at 75 kg · 3:50 /km threshold pace | 1:01:51 | 4:59:48 | 3:12:58 | 9:24:37 |
Pacing plan
- 0 km0%29.2 km/h53:06
- 25.8 km-3.9%48.5 km/h0:13
- 26 km0%29.2 km/h30:29
- 40.8 km-3.4%46.3 km/h0:48
- 41.5 km0.1%28.7 km/h17:55
- 50 km3.7%14.2 km/h1:42
- 50.4 km0%29.2 km/h1:56:15
- 107 km-3.2%45.3 km/h0:42
3 more segments in the full plan.
- Run: reach 4:20 /km and this course gives back 1:32:51.
Where it is decided
On the last 62 km of the bike, which is the single largest block of time in the race.
The engine cuts the leg into segments and two of them swallow everything else. One runs from kilometre 50 to kilometre 107, 56.6 km with nothing in it. The other starts at kilometre 117, just after the second and final rise, and runs 62.3 km into Transition 2. Between them they take 31 percent and 34 percent of the bike leg, and the pacing plan holds a Trained rider at 29.2 km/h across both. No hill arrives to set the power for you. No descent hands anything back. The rider ahead stays close enough to chase.
That second block is the dangerous one, because the climbing is over and the legs still feel fine. Nymiva's course-compiled session for Tallinn is almost comic about it. The engine builds a 159-minute ride holding two work intervals of 75 seconds each, separated by 2 hours 12 of easy riding, because that is what the course actually contains. The honest shape of this bike leg is one long steady effort with two brief interruptions, and whoever rides it that way reaches Unibet Arena with 4:16:44 still in the bank.
Getting it wrong
Three things go wrong here, and the first is the swim. Lake Raku is clear, sandy underneath and deep enough that nothing brushes you, with no current and no surf to argue with. Calm water lets a swimmer hold a pace they have no business holding, and the bill does not arrive for hours. A Trained athlete's swim is 1:19:49, which is 11 percent of the day. It is capable of spoiling the other 89.
Second, the power number. Riders look at 98.2 percent flat and carry their best three-hour figure into a leg that lasts twice that. Two countryside laps mean the second repeats the first, so no new road arrives to take your attention off how good the legs feel, and the aid stations come on a rhythm you learned the first time round. You reach the turn-around near Unibet Arena three times. Only the third one means anything.
Third, the laps on foot. Four passes between Rocca al Mare and Stroomi Beach, the same rise at kilometre 7.4 every time, the same water, the same noise. A marathon with no landmarks left to discover is a marathon run entirely on discipline, and lap one is where that discipline is spent or kept.
Conditions on the day
- 2026high 20 C, low 16 C
- 2025high 21 C, low 13 C
- 2024high 22 C, low 11 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 Tallinn 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
- 11:58:36
- Of the day on the bike
- 52%
- Dimensions scored per leg
- 12
- Season runway shown
- 28 wk
Questions people ask
- How hilly is the IRONMAN Tallinn bike course?
- Barely at all. The organiser's own GPX file measures 179.3 km with 482 m of climbing, and the engine finds only two rises worth naming, 404 m at 3.7 percent at kilometre 50 and 640 m at 3.3 percent at kilometre 116. For a Trained rider they last 102 and 150 seconds.
- What water temperature should I expect in Lake Raku?
- The organiser publishes no water temperature at all for 2024, 2025 or 2026 on its course page, so nobody can tell you honestly. Air temperature is on record, a high of 21 C in 2025 and 22 C in 2024. Check the wetsuit decision in race week.
- How many laps is the IRONMAN Tallinn run?
- Four, between Rocca al Mare and Stroomi Beach along Tallinn Bay, finishing in front of Unibet Arena. The organiser lists 4 aid stations on the run and 8 aid stations on the bike, plus a Personal Need station you pass twice.
- How long should a training plan for IRONMAN Tallinn be?
- The illustrative season on this page runs 28 weeks with five developmental blocks and a two-week taper. That is the shortest runway Nymiva builds for a full-distance triathlon. Your own season starts from your numbers and can be longer.
Course data from the organiser’s published files, analysed 23 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 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.