is China visa required for Shanghai for Canadians arriving by cruise ship for 1 day

My Canadian clients are flying into Tokyo and cruising Singapore on a 28 day cruise. Same ship. Only stop in PRC is for 1 day in Shanghai.
Here is the itinerary:
1st cruise:

Tokyo, Japan - Shimizu, Japan - Kobe, Japan - Kobe, Japan - At Sea - Nagasaki, Japan - At Sea - Shanghai, China - At Sea - Okinawa, Japan - Keelung (Chilung), Taiwan, Province of China - Keelung (Chilung), Taiwan, Province of China - At Sea - Hong Kong, Hong Kong - Hong Kong, Hong Kong

2nd cruise
Hong Kong, Hong Kong - Hong Kong, Hong Kong - At Sea - Ha Long, Vietnam - Ha Long, Vietnam - Da Nang, Vietnam - At Sea - Ho Chi Minh City, Vietnam - At Sea - Bangkok, Thailand - Bangkok, Thailand - At Sea - At Sea - Singapore, Singapore - Singapore, Singapore

Do they need to have a Chinese entry permit or will the 144 hour free transit be sufficient?
Do they have to apply for it before they depart Canada?
I appreciate your assistance.

Marlene
CruiseShipCenters