I'm in the process of planning a trip in China. I plan on returning home from Shanghai Pudong Airport (PVG) but may be arriving in Shanghai from another city via train at Shanghai Hongqiao Railway Station (上海虹桥站). The arrival time at the railway station is 4 hours before the departure time from the airport. Is 4 hours enough time to transfer between the railway station and the airport? Would be keen to hear about the ease of exiting the train station and transfer options.
It is doable but may still be tight if you arrive during peak times. It is easier if you are comfortable with moving with your luggages on a normal walking pace without external help.
To exit the train station, there will be an automated or manual ticket check. For Chinese nationals using Chinese ID cards, a simple tap should suffice to exit. Otherwise, you may need to see a staff member (although some stations are now equipped with passport scanners, I am not sure about Hongqiao) nearby. This should not add more than 10 minutes to the transfer time, as most passengers would simply use the automated kiosks.
There are two direct options. There is a direct bus from the Hongqiao Transit Center (虹桥枢纽东交通中心) to Pudong Airport departure area, costing around 36 CNY. Before Covid, it ran every 30-60 minutes. You can take larger pieces of baggage more easily. It takes 60-70 minutes under ordinary conditions (it takes the freeway), but can easily take way longer due to traffic during peak times (morning, evening, holidays). You will need to walk to the transit center from the train station (10 minutes).
The other option is the Metro line 2, with direct connection from the train station to Pudong Airport metro station. Then you will need to walk from the metro station to the departure area (10-15 minutes). The metro takes 1h30 roughly and runs every 4 - 8 minutes. Note that not all metro trains will have the Pudong Airport as its final destination; you may have to transfer at Guanglanlu metro station.
If you are familiar with the Maglev transfer at Longyanglu station, you may be able to cut travel time by 20-25 minutes. The metro takes 40+ minutes from Longyanglu to PVG whereas the Maglev takes 8 minutes (but you need to take into account the transfer time and schedule).
So to be safe, I would count at least two hours for transfer. If you have larger pieces of baggage that you do not want to take a 1h30 metro ride with you, you need to plan carefully to catch the bus at the right time.
After your arrival at the airport, the time necessary to catch your flight depends on your nationality, language skills, destination (domestic or international), the airline and the terminal, whether you have checked baggage and whether you are eligible for priority check-in and security, and your familiarity with travel and the particular airport. If you arrive two hours before an international flight, it is not not enough at PVG, but the final decision depends on your risk appetite.