The delays will be compounded by a UK Border Force strike on Friday (28 April), which could cause difficulties for people looking to enter the UK from France.
The UK Foreign Office said there may be delays when travelling from ports such as Calais, Dunkirk and/or the Channel Tunnel.
"Trade unions have announced strikes on Thursday 20 April and large-scale demonstrations and coordinated industrial action on Monday 1 May, affecting multiple sectors including transport networks," the FCDO said in a recent travel advisory.
"You should monitor the media, check the latest advice with operators before travelling, avoid demonstrations and follow the advice of local authorities."
