France   / Paris Charles de Gaulle Airport

Paris Charles de Gaulle Airport sprawls across three terminal complexes, seven Terminal 2 sub-terminals, and four runways — and every connection between them depends on your phone. The CDGVAL people mover runs 24 hours linking Terminal 1, Terminal 2, and Terminal 3, but knowing which platform to use and when the next train arrives requires live schedule data. Immigration queues at Terminal 2E can stretch 45 minutes during summer peaks; real-time updates on your phone help you decide whether to sprint for the fast-track lane or wait it out.

Once you clear customs, the SIM-card kiosk queue adds another 15-20 minutes — time you could spend on the RER B platform checking which train reaches Châtelet-Les Halles fastest. CDG's free WiFi requires captive-portal registration and coverage weakens near the RER tunnels and CDGVAL corridors where directions matter most. Your eSIMno plan for France connects through Bouygues, Orange, or SFR infrastructure, the same networks airport staff use, so signal holds from the jet bridge through baggage claim.

Versailles sits 50 km southwest with no direct rail link. The fastest route runs RER B to Saint-Michel Notre-Dame, then RER C to Versailles Château Rive Gauche — roughly 90 minutes with the transfer. Your Palace of Versailles timed-entry ticket lives as a QR code in your email, and the gardens close at sunset regardless of how delayed your train ran. Group chats with family waiting at the Neptune Fountain, Citymapper directions from the station to the palace gates, and Uber pickup coordinates for the return all demand data from the moment you land at Roissy.

Terminal 2E handles most Air France long-haul departures through Halls K, L, and M — the LISA shuttle between Halls L and M adds 10 minutes to your connection if you're switching gates. Terminal 1 serves Star Alliance carriers including Lufthansa, United, and Turkish Airlines, with seven boarding satellites numbered 1 through 7. Terminal 3 handles low-cost carriers like easyJet and Transavia; it sits a 5-minute CDGVAL ride from Terminal 2.

Transit to Versailles

The RER B departs from Aéroport CDG 2-TGV station every 10-15 minutes, reaching Saint-Michel Notre-Dame in about 40 minutes. From there, transfer to RER C toward Versailles Château Rive Gauche — the closest station to the palace gates, a 10-minute walk. The combined journey runs roughly 90 minutes; a through-ticket costs around €13-15. Taxis from CDG to Versailles are metered at around €90-120 depending on traffic via the A1 and A86.