Answered by Borut | Oct. 24, 2024 00:28
Sam, this is all doable under 24 hour visa free transit. It is important to use correct terminology because this is not 24 hour visa, but 24 hour visa free transit, so there is no visa of any kind at all.
Also, it is important to understand that since you will have more than one stop within mainland China, your total transit time is limited to 24 hours counting from your first scheduled landing (Shanghai in your case) until your final departure from mainland China (Fuzhou in your case).
So, if you are within 24 hour time frame, you can proceed with your travel plan with absolute peace of mind. When you land in Shanghai the first thing you will do is to approach 24/144 hour visa free transit counter where you will apply for a temporary entry permit by presenting your flight tickets. After a short check, your temporary entry permit will be granted and you will cross the immigration and formally enter China since your next flight will be a domestic one.
Upon landing in Fuzhou you will be already in China and you will just switch to another airline. It is fine to travel on separate tickets and on unrelated airlines until your flight itinerary complies with 24 hour visa free transit rules that I have described to you. When you are done with all the formalities in Fuzhou, you will cross the immigration in order to exit China and to reach the gate for your flight to Bangkok. Have a nice journey.