Blizzard was the first seal rescued this season and was still learning feeding skills, the charity said.
Ice Ice Baby, the most recent arrival, was found with fishing net tightly around his neck.
His wound was healing and he has been allowed into the charity’s small “first stage pool”, the GSPCA said.
Iceberg Lettuce and Icicle were still gaining weight, it said.
Geoff George, head of marine mammals, said he would look at moving more seals into the larger pool to give them more space once Frosty, Glacier, and Avalanche were released.
He said: “Frosty, Glacier and Avalanche have done incredibly well and are now at the point where they are strong, confident, and ready to make their return to the wild.
“Each has more than doubled their weight since rescue, which is exactly what we want to see before release.”