Marielle Carson, 20, and Latisha Ray, 21, died Saturday morning at Cedar Lake, near Carbondale.
Police say their car went off a boat ramp into the lake. There were five people in the car. Three managed to get out of the vehicle before it was submerged.
Marielle Carson was a student at John Logan College in Carterville.
"Marielle was a very giving person," said her aunt, Tabitha Carson. "Her spirit was strong. She comes from a hard-working family."
The victims' bodies were found by police divers inside the car several hours after they had gone into the lake.