Spanish police said they were holding 21 people who allegedly trafficked cannabis to the city hidden in packs of marble tiles.
Merseyside Police arrested three further suspects.
Spain's Policia Nacional also said five cannabis production centres had been dismantled, and thousands of plants seized.
Footage of part of the operation was posted on the force's Twitter feed.
Twenty-four people have been arrested over a suspected plot to smuggle drugs to Liverpool from Spain.