- Nicaraguan officials had banned sea travel in the area because of bad weather
- The owner of the tourist boat survived and has been detained, a state-run news outlet says
The boat was carrying 32 people -- 25 Costa Ricans, four Americans and three Nicaraguans, Costa Rica's foreign ministry said.
The 13 dead were all Costa Rican, the foreign ministry said, citing the Nicaraguan foreign ministry. Nicaraguan officials did not immediately respond to CNN's request for comment.
The boat, traveling between Nicaragua's Big Corn Island and Little Corn Island, flipped over Saturday near the larger island, Nicaragua's state-run El 19 Digital news agency said.
Some passengers remain missing, the Costa Rican foreign ministry said, but did not specify how many.
El 19 Digital said an unspecified number of people were rescued, including the tour boat's owner, Hilario Blandon.
Nicaraguan naval authorities had banned sea travel in the area because of bad weather and strong winds, but the tour boat proceeded anyway, the state-run news agency said.
Blandon, the boat's owner, has been detained by Nicaraguan authorities, the agency said. Both he and Hellon Absalon Pratt Carter, a crew member, are being investigated for reckless homicide and exposing people to danger, according to police.
Costa Rica's foreign ministry said the search continues for the missing passengers.