Cash believed to total more than €30,000 was discovered by a police sniffer dog inside a van at the Channel Tunnel terminal in Folkestone.
Police Dog Ronnie indicated to officers that there was money inside the vehicle during a routine stop on the morning of Thursday 24 May 2018.
The cash was found hidden within a secret compartment operated by a pulley system and was seized under the Proceeds of Crime Act.
Officers arrested the driver of the van, a 39-year-old man from Guildford, Surrey, on suspicion of money laundering.
He has since been released pending further investigation.
Detective Sergeant Dan Barker of Kent Police said: ‘People who attempt to leave or enter the UK with vast sums of money are always likely to arouse suspicion, especially when it appears attempts have been made to hide that money away.
‘Fortunately not much gets past the noses of our specialist sniffer dogs, who form a vital part of day-to-day policing across the county.
‘We are actively investigating the circumstances of this particular discovery while continuing to disrupt the ability of organised groups to profit from crime.’