Two women and a man have been arrested on suspicion of being concerned in the importation and supply of class A and B drugs and money laundering.
It follows the seizure of nearly £250,000 worth of drugs by the UK Border Agency on the south coast that were destined for Hornsea.
One-and-a-half kilograms of cocaine, five-and-a-half kilograms of ecstasy and one-and-a-half kilograms of MKAT were seized.
A spokesman for Humberside Police said: "Officers from CID, our proactive team, and organised crime group team were involved in executing four separate warrants in the Hornsea area yesterday morning.
"The women and man have been released under investigation."