IRONMAN Portugal-Cascais
Saturday, October 17, 2026, starting at 07:00 · Praia da Ribeira, Cascais
TL;DR. IRONMAN Portugal-Cascais 2026 runs on October 17, with a sunrise start at Praia da Ribeira (~07:00). The bike includes a single lap of the Estoril Formula 1 Circuit and rolls through Sintra, Belém and under the 25 de Abril Bridge. The run is 3 laps from Cascais to Cabo Raso. Official fueling: Maurten + Precision Fuel & Hydration PH 1000. Cut-off 17 hours. Decisive factor: wind on Estrada do Guincho.
Fueling strategy for 12+ hours of racing
In an IRONMAN, keep carbs and hydration on separate tracks. On the bike (5 to 6h), target 90 to 120 g/h. On the run (3.5 to 5h), pull back to 60 to 90 g/h. Sodium 700 to 1000 mg/h on the bike, 500 to 800 mg/h on the run. Caffeine: save it for the marathon (200 to 300 mg between km 21 and km 35).
Carb loading at 10 to 12 g/kg/day across the 36 to 48 hours before. Pre-swim meal at 04:00 for 07:00 start: oats, honey, banana, black coffee. Maurten protocol: 1 Gel 160 (40 g) every 30 minutes on the bike (= 80 g/h) plus PH 1000 bidons (1000 mg sodium/L, zero carbs). On the run: 1 Gel 100 (25 g) every 20 to 25 minutes (60 to 75 g/h), Gel 100 CAF from km 21. Train the Maurten protocol in long sessions.
Course: swim, an epic bike and a 3-lap run
Swim: 3.8 km single loop inside sheltered Cascais Bay, start at Praia da Ribeira, finish in front of the Fortaleza. Typical water 17 to 19C, wetsuit-legal. T1 involves a steep 600 m walk up to the Hipódromo. Bike: 2 laps of 90 km via Estrada do Guincho, Malveira, Sintra (Lagoa Azul, ~150 m), lap of Estoril F1 Circuit, Lisbon (Torre de Belém, Jerónimos, under 25 de Abril Bridge) and back. Run: 3 laps of 14.065 km. Cascais, Estrada do Guincho, Cabo Raso (highest at 197 m) and back.
October weather in Cascais: wind on Estrada do Guincho
October in Cascais offers 16 to 24C of air temperature and 17 to 19C water (almost always wetsuit-legal). Rain probability low (~10 to 15%). The decisive factor is wind on Estrada do Guincho: it can be flat calm or hit 40 km/h. In strong wind, dial back power targets on the first lap.
For hydration in strong wind, add 50 ml/h to bidons. Sodium of 1000 mg/h may be necessary if temperatures climb to 24C. Cabo Raso on the run is the most exposed: use wet sponges and ice on laps 2 and 3. The sunset finish in central Cascais is one of the most cinematic on the European IRONMAN circuit.
Maurten + PH 1000: the official IRONMAN fueling
Confirmed 2024 to 2026 fueling: Maurten (gels) + Precision Fuel & Hydration PH 1000 (isotonic). Gels: Gel 100 (25 g carbs, no caffeine), Gel 100 CAF 100 (25 g carbs + 100 mg caffeine), Gel 160 (40 g carbs, full distance only). Solids: Maurten Solid 160. Isotonic PH 1000 at 1000 mg sodium/L. Bike aid stations every 20 to 25 km, run aid stations every km across 3 laps.
IRONMAN logistics: bag system and drop bags
Athletes village at Cascais Hipódromo with check-in 3 to 4 days before. Standard IRONMAN: blue bag (bike) and red bag (run) in T1 and T2, plus morning clothes bag. Changing tents at both transitions. Massage tents at finish. Central Cascais finish access by 40-minute CP train from Lisbon (Cais do Sodré). Spectator points: Cascais Marina, Guincho miradouros, Estoril Circuit, Cabo Raso.
Comparison with other European IRONMAN events
IRONMAN Cascais is one of the coolest on the European circuit (24C max vs 30C+ in Spain or Italy). It is windier than average. The lap of the Estoril F1 Circuit is unique in the IRONMAN world. The bike with 1,400 to 1,600 m of gain over 180 km is moderate/rolling. For athletes who value scenery and cool weather, one of the best in Europe.
Relevant guides for this race
Frequently asked questions about IRONMAN Cascais
Is IRONMAN Cascais hotter than other European IRONMAN races?
No. It is one of the coolest on the circuit (24C max vs 30C+ in Spain or Italy). It is windier on Estrada do Guincho. Water temperature at 17 to 19C means almost always wetsuit-legal.
Is the swim in Cascais Bay in open ocean swell?
No. Cascais Bay is sheltered with typically low swell. Far more protected than many other European IRONMAN races. For athletes wary of open ocean, a good first full-distance pick.
Is the bike brutal because of the climb into Sintra?
The profile is rolling with 1,400 to 1,600 m over 180 km, moderate. The Sintra climb (~150 m at Lagoa Azul) is the technical highlight, manageable with high cadence. The decisive factor is wind on Estrada do Guincho.
Can I drop bag between run laps?
Yes. You pass through the finish every 14 km and there is a Special Needs option on the second lap. Recommended: small bag with caffeine gel for the final lap plus an extra sodium capsule.
Is the Estoril Circuit lap really unique in the IRONMAN world?
Yes. IRONMAN Cascais is the only IRONMAN that includes an official lap of a Formula 1 circuit. Perfect tarmac, zero traffic, the chance to hold high power without distractions.