Queues of traffic and rail strikes have hit travellers as they embark on trips after many schools across England broke up for the summer holidays.
The Port of Dover said it was taking about 90 minutes for departing passengers to pass through border checks.
It said traffic was moving “according to plan” at the English Channel port in Kent, with 15,901 passengers setting sail for France by 10am on Saturday.
A spokesman said: “If you miss your ferry, don’t worry, you’ll be on the next available sailing.”
P&O Ferries also updated passengers of Border Control queues and urged them to allow extra time to clear security checks.
#PODOVER: There are currently queues at border control, please allow extra time to clear all security checks. Check-in closes 60 mins before your booked sailing time. Rest assured, if you miss your sailing, you'll be on the first available once at check-in ⛴️
— P&O Ferries Updates (@POferriesupdate) July 22, 2023
The summer getaway comes as a walkout by thousands of members of the Rail, Maritime and Transport union (RMT) disrupted services, with some areas having no trains all day.
The dispute over pay, jobs and conditions remains deadlocked after more than a year of industrial action.
An overtime ban by the drivers’ union Aslef also hit services on Saturday.
With reduced services at 14 train companies where the RMT is striking, National Rail warned passengers that the “last trains during industrial action may be earlier than you think, with busier services and stations.”
Passengers were urged to plan their journeys in advance and to check with train operators before travelling.
The RAC said it expected a “busy weekend on the roads” with an estimated 3.1 million leisure trips expected on Saturday and 2.5 million on Sunday.
Meanwhile, the weather is set to be unsettled across the weekend with heavy rain for some, according to the Met Office.
It will feel “disappointingly cool for most” with temperatures around 13C.
It comes after Friday’s highest and lowest temperatures were 22.6C in Frittenden in Kent and 1.6C at Tulloch Bridge in the Scottish Highlands.
After a cloudy start to Saturday, the northern half of Scotland could stay drier with sunny spells and a few showers, while it could become increasingly windy in southern England and Wales, the forecaster said.
For those holidaying in the UK, the first two weeks of the holidays will be a washout but there are indications the weather could become more settled in the second week of August, the Met Office said.
The UK’s poor summer is due to the position of a jet stream which is also pushing high pressure to the south where parts of Europe are experiencing a heatwave.
In an effort to help families travel more easily, children aged 10 and over will be able to enter the UK using eGates across 15 air and rail ports from Monday, the Home Office said.
With passenger volumes expected to return to 2019 levels this summer – and some ports exceeding those volumes – Border Force expects to see more than 34 million air arrivals coming through UK passport control over the coming months.
More than 400,000 children aged 10 and 11 are projected to use eGates this year.