"Everyone aboard the ship has been rescued - they've all been accounted for," a Navy spokeswoman said on condition of anonymity because she was not authorized to speak about the incident.
Brazil's Navy said in a statement that a distress signal was picked up from the three-masted SV Concordia about 5 p.m. (2 p.m. EST; 1900 GMT) Thursday. It was located about 300 miles off the coast of Rio de Janeiro.
Three hours later, an Air Force plane spotted life rafts floating in the ocean where the distress beacon had come from.
The Navy had already informed shipping in the region to be on the alert.
The Navy sent its own rescue ship, but those aboard the Canadian ship were plucked from the ocean early Friday by other vessels.
The Concordia is owned by West Island College International, based in Nova Scotia.
The ship had left Brazil's northeast on Feb. 8 and was expected to dock in Montevideo, Uruguay, on Tuesday.
The head of the school, Kate Knight, says the 64 people included 48 students in grades 11 and 12 and first-year university.
Knight said they got word yesterday morning that a distress signal had been picked up from the vessel and an air and sea search commenced.
She said everyone successfully abandoned ship and got into life-rafts, which are equipped with blankets, medical supplies and food.
She said the life-rafts were spotted from the air around eight o'clock Atlantic time last night.
As far as Knight knows, no one was suffering from any medical issues as a result of the incident.
She said she doesn't know what caused the three-masted Concordia to sink.
The school's Web site says the Concordia was built in 1992 and "meets all of the international requirements for safety."
The 188-foot Class 100A1 yacht, with a gross tonnage of 413, was outfitted with 15 sails and 570 h.p. engines.
The college's site says it gives high school and college students the chance to study various subjects while sailing the world.
Students on the 2009-10 voyage, which departed Canada in September and stopped over in Ireland, Portugal, France, Malta, Turkey, Morocco and Senegal before heading for South America, can study marine biology and practice their ship-keeping tasks while also performing community service in various ports of call.