Why 12 weeks is the sweet spot, and how to set yourself up for success.
So, if you’re reading this we are going to assume you have signed up to a half marathon, which is epic! And whether you are training for your first half or perhaps looking to smash your PB, one of the most common questions runners ask is: “How long do I actually need to train for a half marathon?”
And whilst there’s no one-size-fits-all answer, the most widely recommended - and most realistic - timeframe is 12 weeks. That’s because it’s long enough to build endurance safely, short enough to stay focused, and ideal for creating real, sustainable progress.
So let’s break down why 12 weeks is prime half-marathon prep and key things you should include in your training plan.
Why 12 Weeks Is the Prime Time to Start
Most runners- first-timers and intermediates alike - will follow (and succeed!) with a 12-week plan because it gives you:
1. A Progressive, Safe Build-Up
Jumping too quickly into high mileage is the fast track to injuries, burnout, and frustration. Twelve weeks lets you increase your long run gradually, avoid overloading your joints, and actually enjoy the process.
2. Enough Variety to Improve Everything That Matters
A good 12-week programme balances:
- Easy mileage
- Tempo running
- Strength work
- Long runs
- Recovery days
Remember, its not just about building distance - you’re building resilience, speed, and confidence.
3. A Structure That Keeps You Motivated
A 12-week block is short enough that you can see the finish line from the start. It gives you a clear countdown, tangible progress points, and the right amount of urgency without overwhelming you.
In short: 12 weeks gives you time to prepare properly without wasting time.
