What is the best way to travel from Hong Kong to Shenzhen and how much time does it take

Hi dear, where are you departing from at HK?
If you are at HK airport, you can take the direct ferry at Skypier nearby to Shenzhen. Or you can also take the cross-border buses at the airport to your destination directly.
If you are in the city center, from Wan Chai, Kowloon and Jordan, you can take the direct cross-border coach to Shenzhen.
Generally, the ferry takes about an hour and the bus takes about 1.5h or more.