10k to half marathon plan: a practical guide to move up in distance without burning out
Moving from a 10k to a half-marathon is a natural next step for many runners. You already know how to train. You know how to manage discomfort. What you need now is not motivation, but structure. The half-marathon rewards patience, consistency, and smart progression far more than intensity.
This transition is not about running harder. It is about teaching your body to tolerate longer efforts while staying healthy and confident.
Before we go further, some context. I am Coach Kari, founder of BeFit Runners. BeFit was created as a space where runners can work with
online running coaches and learn how weekly structure, recovery, and progression fit together. We also support runners through
personalized and data-driven online marathon coaching, where plans like this are adapted to real life, not just race goals.
What is a realistic 10k to half-marathon plan?
A realistic 10k to half-marathon plan focuses on extending endurance while keeping most running easy. Speed is already present from 10k training, so the priority is not getting faster but becoming more durable. What needs to be built now is the ability to hold effort longer without accumulating excessive fatigue.
Most runners respond best to a simple structure that includes three to four runs per week, one long run that progresses gradually, and the majority of running done at an easy effort. Rest days are not filler. They are a core part of the plan. The goal is to arrive at race day prepared and confident, not worn down or exhausted.
How long should a 10k to half-marathon plan be?
Most runners need around ten to twelve weeks to move from a solid 10k base to a half-marathon. This timeframe allows the body to adapt in a sustainable way rather than rushing progress.
Over these weeks, connective tissue has time to strengthen, long runs can increase safely, and recovery can keep pace with training demands. Shorter plans often increase injury risk or leave runners underprepared.
Longer plans are absolutely fine as long as consistency remains and fatigue stays under control.
What should a typical training week look like
A standard week in a 10k-to-half-marathon plan should feel simple and repeatable. Complexity is rarely helpful at this stage.
Most weeks include one short easy run, one medium length easy run, and one long run. Additional days are best used for rest or optional cross training rather than adding more mileage. This straightforward structure supports consistency and makes it easier to listen to the body when adjustments are needed.
What easy pace feels like
Easy pace should feel conversational. You should be able to speak in full sentences without gasping or needing to pause for breath. This effort level allows your aerobic system to develop without placing unnecessary stress on the body.
If easy running consistently feels hard, the plan will not work as intended. Easy pace is where endurance is built and where recovery happens at the same time.
The 12-week 10k to half-marathon plan
Below is a clear example of how progression can look when moving from a 10k base to a half marathon over twelve weeks.
Weeks 1 to 3: establish routine
The focus during the first three weeks is consistency. The goal is not distance but rhythm.
During this phase, most runners complete two easy runs during the week and one long run on the weekend. The long run gradually increases from 7 kilometers to 9 kilometers. Other days are reserved for rest or cross-training. There is no speed work at this stage. The emphasis is on building a routine that feels sustainable.
Weeks 4 to 6: extend endurance
These weeks focus on increasing time on feet without increasing intensity.
The long run increases from ten kilometers to fourteen kilometers while weekday runs remain easy and controlled. Effort stays steady, and recovery remains a priority. Runs may start to feel longer, but they should not feel overwhelming or draining.
Weeks 7 to 9: build confidence at a distance
This phase is about durability and confidence.
Long runs progress to sixteen kilometers and then eighteen kilometers. Weekday runs remain mostly easy, though one run may include a short steady section if the runner feels comfortable. Rest days stay protected. Confidence should rise during this phase, not fatigue.
Weeks 10 to 11: absorb the work
These weeks are about letting the training settle.
The long run shortens slightly, total weekly volume decreases, and intensity remains low. This is when the body absorbs the accumulated work. You should begin to feel fresher and more stable, not flat or heavy.
Week 12: race week
Race week is about arriving rested.
Running is limited to very short easy efforts. There is no intensity added and no new workouts introduced.
Extra rest is encouraged. The race takes place at the end of the week, and the goal is to arrive feeling calm, recovered, and ready.
Nutrition considerations during a 10k to half-marathon plan
As mileage increases, nutrition becomes part of training whether you plan for it or not. You do not need a complicated strategy, but you do need consistency.
During a 10k to half-marathon build, the main nutritional goal is to support recovery and energy availability. Easy runs and long runs place different demands on the body, and fueling lightly but regularly helps prevent accumulating fatigue.
Daily nutrition should prioritize regular meals with enough carbohydrates to support training, adequate protein to repair muscle tissue, and fats to support overall energy balance. Skipping meals or underfueling often shows up as heavier legs, poor sleep, or runs that feel harder than expected.
Long runs are also an opportunity to practice fueling habits. As runs extend beyond 75 to 90 minutes, experimenting with small amounts of carbohydrates during the run can improve comfort and reduce late run fatigue. Hydration matters just as much. Even mild dehydration can make easy runs feel disproportionately hard. Paying attention to fluids, especially on longer or warmer days, supports both performance and recovery. If you want to go deeper into fueling strategies, recovery nutrition, and how to support training as mileage increases, you can explore this in more detail in our nutrition for runners blog.
How many days per week should you run?
Most runners transitioning from a 10k to a half marathon do best running three to four days per week.
Running more days is not necessary if long runs are progressing well, easy runs remain easy, and recovery is respected. More training is not better if fatigue begins to build faster than fitness.
What if a long run feels too hard?
If a long run starts to feel overwhelming, the best response is not to push harder.
Slow the pace, shorten the distance, or repeat the same long run the following week. Progression does not need to be perfectly linear to be effective. Consistency matters more than constant increases.
Warning signs you should not ignore
Certain signals indicate that training needs to pause or adjust.
Pain that changes your stride, soreness lasting more than forty eight hours, persistent fatigue, poor sleep, or declining motivation are all signs that recovery is falling behind. These signals call for holding or reducing training, not pushing through.
Should you include speed work in a 10k to half-marathon plan?
Speed work is optional during this transition.
If included, it should remain minimal. Short steady efforts can be useful, but all out sessions are unnecessary. For the half marathon, endurance and durability matter far more than speed.
What this plan is designed to do
A good 10k to half-marathon plan prepares your body to handle the distance with ease and confidence. When training is structured and progression is patient, the half-marathon feels achievable rather than intimidating.
This is why plans like this are often adapted within our personalized and data-driven online marathon coaching, where mileage, recovery, and real-life constraints are balanced instead of ignored.
* Blog Disclosure: Reading our blog does not replace any medical or health consultations with licensed professionals. This blog is created with educational purposes.
Hola, I'm coach Kari
Many of my athletes come to me because they no longer enjoy running, whether due to injury or simply because they're not improving their performance. I want to help you break out of this vicious cycle and enjoy running again. Through my running coaching, you will improve your techniques and become a stronger runner.
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