The drugs, which weighed more than a tonne, were discovered during routine inspections at London Gateway, Thurrock in Essex, on 12 November.
They originated in Colombia and were headed for Antwerp in Belgium, according to customs officials.
The National Crime Agency (NCA) said the find was "a significant hit to the organised crime groups involved".
It follows the discovery by UK Border Force officers of 1,155kg (2,550lb) of cocaine at the port in September.
NCA branch commander Jacque Beer said: "While the UK wasn't the end destination for either shipment, it is likely that at least a proportion would have ended up being sold on our streets.
"These were substantial seizures and will represent a significant hit to the organised crime groups involved, meaning less profit for them to reinvest."
I’d rather live with a good question than a bad answer.