The venue for F1 Monaco Grand Prix 2027 is Circuit de Monaco, Monte Carlo, Monaco. From Lisbon it's roughly 1,486 km — plan on about 2h 34m in the air, landing at NCE. For the festival dates, round-trip fares start around $153; they climb fastest in the last 6–8 weeks.
Sample fares Lisbon → NCE. Final prices and dates are on the partner site.