How to Build a Triathlon Training Plan from Scratch

Pre-built triathlon training plans are useful, but they can’t account for your specific fitness base, race date, available hours, and personal weaknesses. Building your own plan from scratch gives you full control and a deeper understanding of what you’re doing and why. Here’s how to do it properly.

Step 1: Establish Your Baseline

Before writing a single session, answer these four questions honestly: How many hours per week can you consistently train? What is your current fitness level in each discipline? When is your target race? What are your relative strengths and weaknesses across swim, bike, and run?

Be realistic. A beginner with 6 hours per week cannot follow a 12-hour Ironman plan. Build around what is sustainable, not aspirational.

Step 2: Work Backwards from Race Day

• Sprint triathlon: Allow 8–12 weeks of structured training from a decent base.
• Olympic distance: 12–16 weeks minimum.
• 70.3 (Half Ironman): 16–20 weeks from a solid Olympic base.
• Full Ironman: 20–28 weeks minimum, ideally with a 70.3 in the build.

Count back from race day, subtract 2 weeks for your taper, and that gives you your total training window. Divide it into phases (base, build, peak, taper).

Step 3: Structure Your Training Phases

• Base phase (30–40% of total plan) — Build aerobic fitness at low intensity. High volume, low intensity. Establish consistency before adding quality.
• Build phase (40–50% of total plan) — Introduce race-specific intensity. Threshold sessions, brick workouts, longer weekend training. Volume peaks here.
• Peak phase (10–20% of total plan) — Race simulation, short sharp sessions, confidence building. Volume drops slightly but intensity stays high.
• Taper (final 1–2 weeks) — Reduce volume by 40–60%. Maintain a few quality sessions to stay sharp. Rest more than feels comfortable.

Step 4: Balance the Three Disciplines

A common mistake is defaulting to your strongest discipline. Instead, distribute sessions based on your weaknesses. As a general rule for most athletes: swim 2–3 times per week (the discipline most improved by technical frequency), bike 3–4 times per week (the biggest time demand on race day), and run 3 times per week (the discipline your legs feel most after the bike). Strength and conditioning 1–2 times per week is optional but valuable.

Step 5: Build in Recovery Weeks

Every 3–4 weeks, schedule a recovery week where volume drops by 30–40%. These weeks aren’t wasted training — they’re where adaptation actually happens. Skipping recovery weeks is the most common cause of injury, illness, and plateau in triathlon training.

Step 6: The Weekly Template

A simple weekly structure for 8–10 hours of training: Monday rest, Tuesday run intervals or threshold, Wednesday swim + short turbo, Thursday threshold bike, Friday rest or easy swim, Saturday long bike, Sunday long run or brick. Adjust session types by phase — more easy aerobic in base, more intensity in build and peak.

Key Rules for Your Plan

• Never increase total weekly volume by more than 10% from one week to the next.
• Schedule your longest/hardest sessions for when you have the most time to recover afterwards.
• Build in at least one full rest day per week — not active recovery, true rest.
• Be prepared to adapt. Life happens. A missed session is not a failed plan — just move on.