The coroner's office identified the men Monday as 38-year-old Noel Smith of Burney and 32-year-old Nathan Smith of Citrus Heights.
Authorities say the men ended up in the water Saturday evening after their dog fell through the ice at Big Lake in Shasta County. One of the men was submerged for about 20 minutes and the other for about 50 minutes. Rescuers pulled them out but were unable to revive them.
McArthur Volunteer Fire Department Chief Pat Oilar told the Redding Record Searchlight that it appeared the two men took their shirts off before going in after the dog through approximately 3-inch ice.
A third man in their group also went into the water, but managed to swim back to shore. He's being treated for severe hypothermia.
The dog survived, the Record Searchlight reports.
The Big Lake launch area where the men drowned is a popular starting point for duck hunters this time of year.