IRONMAN 70.3 Portugal-Cascais

Fueling strategy for 4h30 to 7h of racing

IRONMAN 70.3 runs 4h30 (elite) to 7h (amateur). The bike tolerates more than the run. Bike (2h to 3h): 80 to 100 g/h, with 1.5 bottles of Maurten Drink Mix 320 (80 g per bottle) + 3 to 4 Maurten 100 gels. Run (1h30 to 2h30): 60 to 80 g/h, gel every 20 min + Coca-Cola and sports drink at the aid stations. Sodium 700 to 1000 mg/h across both (Cascais with wind + sun demands more sodium). Caffeine 200 mg pre-race + 200 mg split across the final 90 min of the bike and run.

Sodium pre-load: 1 g of sodium in 500 ml the day before + 60 min before the gun. Pre-race meal 3h out (04:00 for the 07:00 start): 2 to 2.5 g/kg of carbs (rice, porridge, banana, honey, salt). 30 min before the gun: a 30 to 40 g carb gel + 250 ml of water. Train the Maurten protocol across 8 to 10 long rides + 2 to 3 brick sessions (bike + run). Sodium capsules (Salt Stick) to stack with Drink Mix on the warmer days.

Course: bay swim, Estoril F1 bike, coastal run

Swim 1.9 km: single loop in Cascais Bay, start at Praia da Ribeira, sheltered water. Typical temperature 18C, wetsuit-legal. Bike 90 km: heads out along the Portuguese Riviera, past Estrada do Guincho, runs a single loop of the Estoril F1 Circuit, then returns. A unique feature in the IRONMAN 70.3 calendar. Run 21.1 km: along the Estoril-Cascais coast, mixed surface (boardwalk + tarmac), loop with Atlantic views. Iconic points: Praia da Ribeira, Cascais Bay, Boca do Inferno, Guincho, Autódromo do Estoril, Cascais Marina.

October in Cascais: wind and moderate sun

October brings 16 to 24C of air temperature (high 24C, low 16C). Water around 18C: wetsuit is legal up to 24.5C of water temperature, so October in Cascais is a near guarantee. Wind can pick up at Guincho, changing the bike strategy. Low to moderate chance of rain. On a 5h+ effort, the wind is the differentiator.

For hydration in wind and sun: 750 to 1000 ml/h on the bike, adjusted to your sweat rate. Watch out for hyponatraemia (low sodium) in athletes who over-hydrate without sodium. A salt pre-load + Salt Stick capsules during the race cover this. For an unusually cold day (below 16C), consider a short sleeve top + thin wind-proof gilet on the bike.

Aid stations: official Maurten

Bike (90 km): 2 to 3 aid stations with water + sports drink. Official brand: Maurten (Gel 100, Gel 100 CAF, Drink Mix 160 or Gatorade Endurance depending on the 2026 contract, check race-week info). Run (21.1 km): aid station every 2 to 3 km with water, sports drink, Maurten Gel 100, Coca-Cola, fruit, sponges, ice. Maurten has been an official IRONMAN partner since 2021. For a consistent strategy, train with Maurten on every long session for at least 8 weeks beforehand.

Logistics: A5 from Lisbon, colour-coded IRONMAN bags

Access: A5 motorway from Lisbon (30 min) or the CP Cascais line. Lisbon airport is 30 min away. Packet pickup at the athlete village, typically Thursday and Friday before the race. Standard IRONMAN bag drop: blue bag (bike), red bag (run) + morning clothes bag. Family along the course: easy spot at the Cascais Marina (you pass several times on the run loop), Boca do Inferno, Guincho. Finish line in the centre of Cascais with pedestrian and CP train access.

Why IM 70.3 Cascais is a European benchmark

2025 Athlete Choice Award: 2nd most recommended IRONMAN 70.3 in EMEA. The only IRONMAN 70.3 with a loop on an F1 circuit (Estoril). The "vibrant and vivacious" feel of the Portuguese coast. "3,000 hours of sun per year" climate. Entries typically sell out within hours. Co-staged on the same day as the IRONMAN Full (3.8 + 180 + 42.2 km), which amplifies the celebratory atmosphere. For 70.3 World Championship qualifying, slots are available (confirm 2026 allocation for Marbella or Penticton).