Hundreds of thousands of Hong Kong residents travelled out of the SAR on the first day of the Easter break on Friday.
As of 10am, more than 254,000 people had left the city, according to the Immigration Department.
Around one in five departed via the Lo Wu control point, with the crossing at Lok Ma Chau the next busiest.
At one point, there were 90 minute waits for drivers heading to the mainland via the Shenzhen Bay checkpoint.
The MTR temporarily brought in special arrangements on the East Rail Line as part of crowd control measures.
Trains departing from Admiralty only went as far as Tai Po Market, where people heading to the border had to change to other trains.
As of 10am, Hong Kong had welcomed more than 56,000 visitors. The largest number arrived by plane, with Lo Wu the second busiest arrival point.
