Cash totalling £40,000 was seized by Kent Police officers at the Channel Tunnel on Saturday 10 April 2021.
The money was identified during three separate vehicle checks at the outbound border controls, resulting in three arrests.
At around 5.20pm a 40-year-old man and a 41-year-old man, from London, were arrested on suspicion of money laundering after each was found in possession of £10,000 cash.
Then at around 7pm a 39-year-old man from Southampton was arrested on suspicion of money laundering after also being found in possession of £10,000 cash.
All three were released from custody pending further enquiries.
A further quantity of cash totalling £10,000 was seized from another man using legislation under the Proceeds of Crime Act.
No arrests were made but enquiries into how he came to be in possession of the money are ongoing.