Nice
 

We are departing from Chicago to London with a connecting flight from Nice to Barcelona. We have 10 hour layover as the airline has recently changed the itinerary. Are you allowed to go out to spend a day in Nice? Do we have to go through immigration? Appreciate input.

If you want to leave the aiport even for a few hours you have to go through immigration the same as if you were leaving the airport for a few days. The immigration requirements in France depend on your own nationality. See google to find the French embassy or consulate located in your country of nationality for the specific requirements.

I don't know the Nice airport for international flights, but typically you would have to go through "immigration" (i.e., passport check) even if just going from a London flight to a Barca flight. Since London is non-Schengen, you would need to have your passport stamped to enter the Schengen zone, before connecting to (Schengen) Barcelona - - even if you are just transiting Nice.

Unless you are of a nationality with special visa considerations, it's a brief wait and a quick passport stamp whether you just transfer planes or go into town. Your luggage should check through to Barcelona, where you would technically have the bags clear customs, but that is typically a waive-through.

By all means get the #98 bus into town (the ticket is also good for travel within Nice on trams or local busses, and the return to the airport) and enjoy the sun, sights, and food.

Actually immigrations is inside the secured area just before you go to your gate. If you already have your boarding pass, you will go through security check, then immigrations, then your gate. And I would go into Nice for sure!!! The bus is 4€. Have fun in my favorite city.

Nice Airport isn't that big, just busy, so you won't have trouble navigating your way around - but you would have trouble keeping yourselves amused for 10 hours (there are only so many magazines in the Relais!). As has been mentioned, you will likely go through immigration in London as you are connecting to a European flight - not sure of your booking, but if you are changing Terminals (which is likely) then you will go through immigration. Your bags, however, should be checked the whole way throught Nice/Barcelona - check with your airline at your departure point, you may need to collect bags in Nice for the final leg to Barcelona. If so, there is a Left Luggage service at the airport, just go to the Information/Service Centre in your arrival Terminal.

Back to Nice for a day. You can take a bus (15-20mins) from either Terminal 1 or 2 (different busses, but not hard to find) into the city, or a taxi if you prefer. Not sure of the time of year you're in Nice, but if you felt like a lie on the beach you could treat yourselves to a beach lounge at one of the private beaches and spend the day in the sun with a restaurant for lunch close by (about 10 steps to be precise!). They have showers onsite too so you can freshen up before your next flight. Or you could get to the centre of Nice and go for a walk up Le Chateau, which is the rock and ruins at the northern end of Promenade des Anglais. It might be good to do after a long flight, and the views are great. If shopping is more your thing, head to Avenue Jean Medecin and walk both sides, as well as the pedestrian area of Rue Massena. And of course take a long stroll through the alleys of the Old Town (Vieux Nice). Lunch in one of the better restaurants around the Cours Saleya would also be good.

Make sure you allow enough time to get back to the airport for your Barcelona flight as the traffic on the Promenade can get gridlocked in the afternoons.