How to train for a half marathon
Race Training
The half marathon is the best-value race in running. Long enough to be a genuine test, short enough that you can race one every few months without wrecking your year.
The short answer
Train for a half marathon with 12 to 16 weeks of consistent running: 4 to 6 runs a week, 80 percent easy, one weekly threshold session, one long run building to 100 to 140 minutes, and progressively more running at goal half marathon pace as the race approaches. Half marathon pace sits between your threshold and your marathon pace, and the training that matters most is sustained work near that line.
What the half marathon demands
For most runners, half marathon pace is close to threshold — perhaps 5 to 15 seconds per kilometre slower. For faster runners it sits nearer to it still.
So you need three things: a threshold high enough that goal pace is sustainable, an aerobic base deep enough that 21.1km does not empty you before the finish, and enough specific work at goal pace that your legs recognise it on the day.
Fuelling matters too, though less than in the marathon. Most runners will want something at around 45 to 60 minutes, and that is worth practising rather than improvising.
The shape of a half marathon block
Weeks 1–5: base
Build weekly volume and get the long run out to 90 minutes. One threshold session, moderate. Hills weekly. Strides twice a week. Nothing clever.
Weeks 6–11: build
Threshold volume rises to 30 to 40 minutes of work. The long run extends to 110 to 130 minutes and starts to include some work — the last 20 to 30 minutes steady, or a block at goal pace in the middle.
A second quality session appears for those handling the load, usually shorter reps at 10km pace to keep the top end honest.
Weeks 12–14: specific
Now the sessions look like the race. Long continuous blocks at goal half marathon pace: 3 x 15 minutes, or 2 x 20 minutes, or a 10km time trial at goal pace inside a longer run. The long run peaks around 130 to 140 minutes, or about 2 hours 20 for most people.
Final 10–14 days: taper
Volume down 40 percent over two weeks, intensity retained. Long run comes back to 70 to 80 minutes. One short race-pace session in the final week.
The three sessions that matter most
- Threshold floats: 5 x 6 min at threshold, 90 sec float. Builds the ceiling that half marathon pace sits under.
- Goal-pace blocks: 3 x 15 min at goal HM pace, 2 min float. The most specific session in the block.
- Progressive long run: 100 min, with the final 30 min at goal pace. Teaches you what the last 8km will feel like.
Coach's note
Floor and Jacob both came through a half and full build together, and the thing that moved the needle for both of them was not the hard sessions — it was getting the long run genuinely easy and then adding work to the back end of it. A long run at 5:30/km when it should be at 6:00/km will not obviously hurt you on the day. It will quietly cost you Tuesday's session, and then next week's long run, and by week nine you cannot understand why nothing is improving. Long runs are aerobic development, not a weekly test.
A typical build week
- Monday: Easy 45–55 min
- Tuesday: Threshold — 5 x 6 min, 90 sec float
- Wednesday: Easy 50–60 min + strides
- Thursday: Easy 45 min or steady 40 min
- Friday: Easy 35 min or rest
- Saturday: Quality — goal-pace blocks or 10km-pace reps
- Sunday: Long run 110–130 min, easy to progressive
How to race it
Start 5 to 10 seconds per kilometre slower than goal pace for the first 2km, settle onto goal pace from 3km to 15km, and then decide at 15km whether there is more available. There usually is if you were patient early.
The hard part of a half marathon is between 14 and 18km. That is where the effort rises without the pace changing, and where the race is either held together or lost. Practise that feeling in training — it is exactly what the last 30 minutes of a progressive long run gives you.
Fuel at about 45 minutes and again at 75 if you are out longer than about 100 minutes. Drink to thirst. Nothing new on race day.
Common mistakes
Not enough goal-pace running. Plenty of runners arrive at the start line having never run more than 5km at their goal pace. The race asks for 21.
Long runs too hard. The most common error I see, and the most expensive.
Too long a taper. A half marathon does not need a marathon taper. Ten to fourteen days is right; three weeks leaves most runners flat.
Choosing a goal pace from a calculator rather than from evidence. If you cannot complete 3 x 15 minutes at goal pace three weeks out, that is not your goal pace.
Racing a half in Wellington
The Wellington Marathon weekend in late June includes a half, and the Round the Bays half in February gives you a flat waterfront course when conditions cooperate. Both are good targets, and they sit at opposite ends of the year, which makes them a natural pair for a two-block season.
For training ground, the Hutt River Trail is the standout — 29km of largely flat multi-use path with nine bridges giving you loop options, which means you can build a long run of almost any distance without repeating yourself or stopping for traffic. The Petone Esplanade covers the same need over shorter distances.
Realistic expectations
Off a genuine 14 to 16 week block, a runner with a year or two of background will commonly take 3 to 8 minutes off a half marathon. Experienced runners take 1 to 3.
The half marathon is also the distance where good pacing is worth the most. A runner who goes out 15 seconds per kilometre fast will lose two to four minutes over the back half. That is a bigger swing than most training blocks produce, and it costs nothing to get right.
