AI-built open water swimming plan
12 weeks for open water crossing (1.5-5 km). EntrenAI structures pool sessions + open water swims (OWS), teaches sighting, drafting, navigation, wetsuit management and depth fear management. For pool swimmer with 1500m base.
Updated
What is an open water swimming plan?
The open water swimming (OWS) plan is designed for swimmers with solid pool base wanting to transition to crossings in sea, lake or river (1.5 km, 3 km, 5 km, 10 km).
Open water-exclusive skills the plan develops:
- Sighting (look forward every 4-6 strokes): orient toward buoys/reference point
- Drafting: swim behind another swimmer (-30-40 % energy expenditure)
- Navigation: knowing direction without lane markers
- Wetsuit management: how to enter, exit, avoid chafing, maintain temperature
- Fear management: dark water, depth, creatures, swell
- Bilateral stroke: alternating breathing for both-sides visualization
- Acceleration/stop at buoys: direction change technique
Differences vs pool swimming:
- No wall rest: continuous stroke for 30-90 min without stopping
- Strong initial acceleration (mass start) for 200-500 m
- Sighting every 4-6 strokes (vs only breathing in pool)
- Navigation without lane markers or fixed depth
- Water temperature (12-22°C typical Mediterranean, requires wetsuit or resistance)
- Swell, currents, wind affect pace
Plan combines pool (technique + intervals focus) with open water swims (OWS) when temperature permits (May-October in Spain).
Sea swimming costs 5% more: the paces already account for it
With no lane ropes, no wall to push off and the sea moving, the same CSS gives a real pace 5% slower. The table takes that into account for the three usual open-water distances.
| Pool /100 m | Open water /100 m | 1,500 m | 1,900 m (70.3) | 3,800 m (Ironman) | |
|---|---|---|---|---|---|
| CSS 2:10 | 2:10 | 2:17 | 34:08 | 43:14 | 1:26:27 |
| CSS 1:50 | 1:50 | 1:56 | 28:53 | 36:35 | 1:13:09 |
| CSS 1:35 | 1:35 | 1:40 | 24:56 | 31:35 | 1:03:11 |
Your AI-generated plan
1. Initial validation.
- Swimmer with 1500m pool base (can swim 1500m without stopping, 25-35 min pace)
- 6+ months consistent pool experience
- No critical fear of deep water
- Pool access (4 sessions/wk) + open water (lake, sea, river) when temperature permits
- 5 sessions/wk commitment, 60-90 min each
- Cardiovascular health clearance
2. Typical weekly structure:
Warm season (May-October, water >18°C):
- Monday - Pool technique + intervals (60 min)
- Tuesday - Pool threshold (60 min)
- Wednesday - Rest or pool recovery (45 min)
- Thursday - Pool speed + sprints (60 min)
- Saturday - Open Water Swim (OWS) (45-90 min by plan phase)
- Sunday - Pool long swim or rest (60-75 min)
Cold season (November-April, water <16°C):
- 5 pool sessions/wk (no OWS)
- Focus on maintaining technique + wetsuit adaptation in pool if gym permits (some gyms allow wetsuit on specific days)
3. 4-phase periodization (12 wk):
Base (4 wk - exclusive pool):
- 8-10 km/wk pool volume
- Bilateral stroke technique focus (every 3 strokes breathing)
- Sighting drills in pool (every 6 strokes look forward)
- Resistance: 1500-2500 m continuous
- Threshold intervals: 4×400 m, 3×500 m
Build (4 wk - OWS introduction):
- 10-12 km/wk volume (including 1 OWS of 30-45 min)
- First OWS wk 5: 800-1000 m with wetsuit, calm water
- Practice sighting + drafting (if group)
- Increase OWS to 60 min wk 8
Specific (3 wk - dominant OWS):
- 12-15 km/wk volume (including 1 OWS of 60-90 min)
- Long OWS simulating goal distance (3 km, 5 km, etc.)
- Practice with swell, currents
- Test water temperature without wetsuit (if goal distance requires)
Tapering (1-2 wk):
- Reduced volume (-30 %, then -50 %)
- Maintain technique + sighting
- 1 OWS wk -2 at 60 % goal distance
- Race/crossing wk 12
4. OWS-specific technical drills:
Sighting drills (in pool):
- Crocodile: every 6 strokes, briefly raise eyes forward (without raising full head) — eyes look forward, mouth to side to breathe
- Repetition: 4×100 m with sighting every 6 strokes
- Consolidation: 1500 m with sighting every 4 strokes
Bilateral stroke:
- Breathing every 3 strokes (left + right alternating)
- This develops symmetry + allows both-sides visualization in OWS
- 4×200 m breathing every 3 strokes
Drafting (in group):
- Position 1: directly behind head (nose touches feet of front swimmer)
- Position 2: slightly lateral (head at hip side of front swimmer)
- Practice in pool with partner or in OWS group
- Reduce effort ~30-40 % in draft
Wetsuit management:
- Enter: lubricate arms/neck with vaseline or specific lubricant (BodyGlide, ButtR)
- Exit: lower zipper, drop pectoral first, then arms
- Maintenance: rinse fresh water post-OWS, dry in shade, no harsh folding
The open-water course: sighting and drafting
What in the pool is a black line, in the sea is sighting every 6-8 strokes and choosing well whom you swim behind. The plan's open-water sessions practise both with real buoys.
Who is this plan for?
- Pool swimmer with 6-12 months base wanting to transition to OWS. 12-week plan from pool-only to first 1.5-3 km crossing.
- Triathlete preparing triathlon swimming segment. 10-12-week plan (triathlon swim segment is OWS).
- Adventurer/explorer wanting to cross lakes, rivers, sea distances (Strait of Gibraltar requires more advanced plan but similar base).
- Amateur OWS swimmer preparing 5-10 km crossing (Bay of Santander, Vigo crossing, Catalina Channel relays). 12-week plan focus resistance + technique.
Only swim pool without OWS goal? Beginner or technique swimming plan better. Doing full triathlon? Specific triathlon plan (includes OWS + bike + run integrated).
Metres per week across the 12 weeks
From 6 to 14 km a week, with a taper in the final week. The thin bar is the longest continuous swim of the week, which reaches 3 km.
- Base
- Build
- Specific
- Taper
- Deload
- Longest continuous swim
Your first weeks, in detail
Week 7
Advanced build — first extensive OWS, consolidated sighting technique| Day | Session type | Detail | Duration |
|---|---|---|---|
| Monday - Pool technique + intervals | Technique + Z3 threshold | - **Warm-up 400 m** (200 m freestyle + 200 m crocodile sighting drill) - **Drill set**: 4×100 m sighting every 4 strokes + 200 m bilateral 3 strokes - **Main set: 5×400 m @ threshold pace (~80 % HRmax)** with 30s rest - **Cool-down 200 m gentle** - Total: ~2700 m | 60 min |
| Tuesday - Pool threshold continuous | Sustained Z3 | - 400 m progressive warm-up - **Main set: 2000 m continuous @ sustainable threshold pace** (~30s/100m of your 100m PB pace) - 200 m gentle - **Sprint set: 4×50 m at max** with 60s rest - 200 m cool-down - Total: ~3000 m | 55 min |
| Wednesday - Pool recovery | Easy Z1-Z2 | - **2000 m continuous easy Z2 pace** (conversational pace if possible) - Focus technique + relaxation - Bilateral stroke entire time | 45 min |
| Thursday - Pool speed + sprints | Z4-Z5 anaerobic | - 400 m warm-up - **Drill set**: 4×100 m long stroke drill + high cadence - **Sprint set: 8×100 m @ 5K pace** with 30s rest - **Short sprints: 6×50 m max effort** with 60s rest - 300 m cool-down - Total: ~2700 m | 60 min |
| Friday - Rest | Recovery | Full rest or 30 min walk. | 0-30 min |
| Saturday - Open Water Swim (OWS) 60 min | OWS technique + sighting + drafting | - **Arrive beach/lake 30 min before** for wetsuit prep - **Lubrication**: vaseline neck/armpits/thighs (chafing zones) - **Water warm-up: 200 m gentle** + activations - **Main set: 60 min continuous** ~3 km at conversational Z2 pace - **Sighting every 4-6 strokes** (buoy or reference) - **Drafting if partner available** - Progressive water exit | 60 min |
| Sunday - Pool long swim | Sustained Z2 | - **3000 m continuous Z2** (no wall stops, simulating OWS but pool) - Bilateral stroke - Sighting every 8 strokes - Focus efficiency + sustainable rhythm | 60-65 min |
These examples are real extracts from the EntrenAI planning engine. Your personal plan adjusts to your level, equipment and availability.
Equipment needed
EntrenAI automatically substitutes any exercise if you don’t have the gear.
- Competition swimsuit + training swimsuit (no surfer shorts)
- Polarized mirror goggles for OWS (Aquasphere, Vorgee, Speedo) — exterior water vision
- **Open water wetsuit** (4-5 mm body, 3-2 mm arms): Orca, BlueSeventy, Zone3 (€250-450)
- **Anti-chafing lubricant** (BodyGlide, ButtR €10-15) — IMPERATIVE for wetsuit
- White/luminous silicone cap (visibility)
- **Safety buoy**: New Wave Swim Buoy or similar (€30-60) — flotation + visibility
- Waterproof GPS watch with OWS mode (Garmin Swim 2, Garmin Fenix, COROS)
- **Ear plugs** (Mack's Pillow Soft) — cold water can cause dizziness
- Water-resistant SPF 50+ sunscreen for OWS
- Large microfiber towel post-OWS
- Water bottle + energy bar post-OWS
- Swimming partner or group (NEVER alone in OWS)
What most people get wrong (and how to avoid it)
- 1
Doing first OWS without partner
Open waters have real risks (cramps, hypothermia, swell, marine wildlife). NEVER first OWS alone. Minimum 1 partner or organized OWS group. EntrenAI does NOT recommend solo OWS under any circumstance, especially beginner.
- 2
Forgetting wetsuit lubrication
Without neck/armpit/thigh lubrication, wetsuit produces severe chafing in 30-45 min. Vaseline or BodyGlide on critical zones BEFORE putting on wetsuit. Without this, first OWS ends with wounds taking days to heal.
- 3
Skipping sighting technique in pool
Sighting every 4-6 strokes is UNIQUE OWS skill. Don't practice in pool? First OWS you lose orientation every 100 m, swim zigzag, real distance is 30-50 % more than straight line. Sighting drills 1×/wk minimum.
- 4
Doing OWS in too cold water without preparation
Water <14°C without gradual preparation = hypothermia + cold water shock (cardiac risk). Gradual adaptation: start with 18-20°C, lower 1°C every 2-3 wk. Without preparation or full wetsuit, NO OWS <16°C.
- 5
Skipping pre/post long OWS nutrition
OWS 60+ min in cold water burns 600-1000 kcal. Without pre-meal (3h before: oats + banana) and post-meal (30-60 min after: 30g protein + 60g carb) = insufficient recovery + accumulated fatigue in next session.
- 6
Not respecting 'never swim alone' rule
Solo OWS is main cause of amateur drowning deaths. Cramps, sudden fatigue, dizziness, any emergency without partner = vital risk. Minimum 1 partner, ideally group + shore support (kayak, paddleboard).
- 7
Practicing OWS with wetsuit ALWAYS
Goal crossing allows wetsuit? Practice with. Doesn't allow (some classic crossings, FINA rules for >20°C)? Adapt to without wetsuit before. Without wetsuit: 30-50 % more effort, better hip/leg flotation.
- 8
Comparing pool pace with OWS
Your OWS pace will be 10-30 % SLOWER than pool by: swell, sighting, no wall to slide off, wetsuit clothing (resistance), zigzag navigation. Pool pace 1:30/100m? Realistic OWS 1:50-2:00/100m. Calibrate expectation.
Other Swimming plan variants
Back to the general Swimming plan
- AI-built beginner swimming planA beginner swimming plan that builds technique and aerobic capacity from scratch: 8-12 weeks, 3 sessions a week and 1,000 m continuous at the end.
- AI-built swimming technique planA swimming technique plan with 12 weeks of freestyle drills for stroke, body position and breathing, for swimmers with a base who want a faster 100m pace.
- AI-built 1500m swimming planA 1500m swimming plan that takes you from 1000m continuous to a sustainable 1500m in 12-14 weeks, with efficient technique and calibrated 100m splits.
Frequently asked questions
>20-22°C water generally comfortable without wetsuit for distances <3 km. 18-20°C: acceptable with wetsuit or after gradual adaptation. <16°C: requires full wetsuit + experience. <14°C: only experienced swimmers with specific preparation.
Highly recommended, not strictly mandatory by law in Spain. Benefits: (1) flotation if cramp or fatigue, (2) visibility for boats/jet-skis, (3) keys/phone/food storage. New Wave Swim Buoy €40 = investment that can save life.
30-40 % energy expenditure in correct position (directly behind swimmer). This means: solo pace 1:50/100m, in draft you can maintain 1:40/100m with same effort. Critical in long crossings and triathlon swim segment.
Stop + float on back first. Deep breathing 60s. Calm down. Don't swim immediately back to land — distance can exhaust. Call partner/kayak with sharp shout. Alone? Wait for calm + swim SLOWLY with conservative pace.
Pre-OWS (3h before): 80g oats + banana + water. During OWS >75 min: gel 30 min before + at mid-pause (buoy). Post-OWS: 30g protein + 60g carb in 30-60 min. Hydration: water + electrolytes before (you lose much salt in salt water, irony).
Gradual strategy: (1) First OWS: calm water (lake lake lake, not open sea), clear day, short distance 500m, partner visible nearby. (2) Second OWS: 800m, same conditions. (3) Third OWS: introduce protected sea. Progressive adaptation = fear disappears in 4-6 OWS.
Options: (1) Longer crossings (5-10 km): advanced OWS plan + specific adaptation. (2) Triathlon (combine OWS + bike + run): integrated triathlon plan. (3) Marathon swim (>10 km): requires specific ultra-endurance plan.
Extreme crossings (12-50 km in cold water) require 12-24 months specific preparation + expert accompaniment + cold water adaptation + during-ride nutrition. Standard 12-week OWS plan is base, NOT enough for world-class crossings. Specific human coach required.
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