12-week half-marathon training plan: Your complete guide

Three months of training can race by – especially when you’re building toward the starting line of a half-marathon. 

This 12-week half-marathon training guide walks you through the different phases of training – from what to consider before you start, all the way to race day and through the finish line.

Before you begin your half-marathon training schedule, take stock of where you are. Your goals, current fitness and injury history all shape how the next 12 weeks should look, and how smoothly you’ll progress towards race day. 

Start with these essentials:

- Assess your starting point: Your current mileage and target pace will guide how much volume and intensity you can safely handle from week one. - Choose a plan that fits: Training isn’t one-size-fits-all. A runner building toward their first half-marathon needs a different approach than someone chasing a faster finish. Match your plan to your experience, and increase gradually. - Factor in injury risk: If you’re managing a niggle or returning from injury, adapt early. Cross-training – like swimming or cycling can replace some easy mileage while keeping your aerobic base strong. - Check your gear: Reliable road-running shoes matter. The right pair supports consistency, comfort, and confidence as mileage builds.

The goal of the first four weeks is simple: consistency. Start steady, find your rhythm, and let your body adapt to regular running.

Focus: Prioritize easy mileage with a mix of short runs and one longer run each week. Most runs should feel conversational. Short runs typically sit around three to four miles (or five to six-and-a-half kilometers) with a weekly long run building gradually toward six to eight miles (10 to 13 kilometers).

Goal: Establish a solid mileage foundation and a routine your body can handle week after week.

With a base in place, you can begin to layer in intensity. Consistency still matters most, but now you’re asking your body to work a little harder.

Focus: Increase overall mileage and introduce speed work once or twice a week. This may include interval training or tempo runs at a comfortably hard pace. Weekly runs may range from four to nine miles (six to 15 kilometers), depending on your experience and recovery.

Goal: Improve aerobic capacity, running economy, and confidence at faster paces.

The final stretch is about refining. You should feel comfortable with the distance by now. From here, trust the work you’ve already done.

Focus: Gradually reduce overall volume while maintaining a touch of intensity. Shorter runs keep your legs responsive, while a few controlled longer ones support endurance. It’s normal to feel restless or anxious as mileage drops – often called “taper crazies” – but rest is part of the training. After all the work you’ve put in, give your body the chance to repair and rebuild.

Goal: Arrive at the starting line feeling fresh, strong and mentally ready.. You should feel comfortable with the distance by now. From here, trust the work you’ve already done.

Race week is all about preparation. You’re not going to gain any fitness in the last week, so keep things familiar and low-stress.

- Dial in hydration and pacing: Use fueling strategies that worked in training. Start conservatively and break the race into thirds to stay controlled. - Test everything before race day: Nothing new on race day is a repeated mantra for a reason. Shoes, tops, running shorts, breakfast, and fueling should all be familiar by now. - Prepare early: Pin your bib and pack your bag ahead of time to avoid last-minute stress. - Study the course: Review the map and note key landmarks. If possible, spend time on the course to understand the terrain and plan your effort.

With your plan in place, these principles help you train more consistently and adapt when things don’t go perfectly.

- Stick to a structured plan: Use the schedule above as your framework, but allow for flexibility. Rest days, work travel, or unexpected fatigue are part of training. Adjust without abandoning the plan. - Build strength beyond running: Cross-training and strength work support durability. Exercises like squats, deadlifts and overhead presses strengthen your entire body. - Fuel for the work you’re doing: Half-marathon nutrition needs vary, but consistent carbohydrate intake supports training volume, while protein helps repair and rebuild muscle. - Prioritize recovery: Easy days matter. Active recovery keeps blood flowing, reduces lingering soreness and supports long-term consistency – a key factor in reducing injury risk. - Practice race-day fueling: Dial in breakfast, hydration, and mid-run fueling during training so nothing feels unfamiliar on race morning. - Strengthen your core: A stable core supports efficient form as fatigue sets in. Exercises like dead bugs, planks, and bird dogs help maintain posture and control late in the race.

This 12-week half-marathon training guide is designed to prepare you for race day, physically and mentally. But the real work happens in the weeks you show up, adapt, and keep going.

Whether this is your first half-marathon or your fifteenth, trust the training you’ve put in. Arrive at the start line ready, focused, and ready to run your race – and it’s yours.