Dozens of stowaways hiding in appalling conditions in a ship's containers gave themselves away by laughing.
The 36 Chinese illegal immigrants were found in Vancouver when the captain heard their giggles, a customs spokeswoman said.
The 30 male and six female stowaways were in good health - even though their containers were full of fasces and urine.
Royal Canadian Mounted Police spokesman Grant Learned says the captain and crew of the ship called Pretty River will not be charged as they notified authorities quickly.
Immigration Canada has imposed a Canadian $1.08m (around £480,000) security deposit on the ship's owner to cover the cost of possible future deportations, administrative costs and fine.