Crossing the Shenzhen Bay Bridge on New Lantao Bus route B2 from Tin Shui Wai in the New Territories of Hong Kong to the Shenzhen Bay checkpoint in early April 2021. Due to quarantine policies for travelers entering Mainland China, there was little traffic on this route and I was the only passenger on the bus for the entirety of the journey.
As there is a small area on the Mainland side of the bridge that is under the jurisdiction of Hong Kong Immigration authorities, it is possible to cross the bridge by bus or taxi and return to Hong Kong by the same means without crossing the border or entering Mainland China. The floating oyster or abalone farms are visible on the Hong Kong side of Shenzhen Bay during the crossing.