They were on a day trip to go snorkeling.
As they jumped from the sinking boat, some took pictures.
Students say they got little help from the crew and had to fend for themselves.
One of the students, Lisa Chang, did not survive the ordeal. Friends and family remembered her during a vigil last night.
Mexican officials say the boat was authorized to carry only 80 people. But it was overloaded with about 200 people on board.
The touring company that organized the trip has suspended operations while the tragedy is investigated.
