The Servicio Nacional de Guardacostas intercepted a boat carrying 1,400 kilos of marijuana Sunday off Limón in the Caribbean.
The crew of four tried to dump some of the packages into the sea, but they were recovered, said the coast guard.
The craft was flying a Costa Rican flag, and three of the four men on board were Costa Rican, said the coast guard.
The interception was about 12 nautical miles off the Limón coast.
Although Costa Rica produces many tons of marijuana, the product from Jamaica is said to be of higher quality.
Security officials said that eight tons of marijuana have been confiscated so far this year.