The UK Foreign Office said high levels of traffic are expected on all routes across the channel from 7 April.
It comes after a critical emergency was declared at the Port of Dover last weekend (31 March), when passengers faced 17-hour queues due to slow processing and an unexpected number of coaches.
"There is a possibility of delays over the Easter bank holiday weekend as high levels of cross-channel traffic on all routes are expected," the FCDO advised.
"Check for latest information with your travel operator, including their advice on how early you should arrive at the terminal.
"Where possible, you should make sure you have a confirmed booking before you travel and ensure you are fully prepared for your trip with enough food and water."
