More than 100 rescue personnel worked for 14 hours to dig the girl out safely, according to reports in several Swiss dailies.
"In a very short time we had to clear blocks of rock centimeter by centimeter," said Matthias Lorenz, head of the Aletsch fire department, cited by Swiss public broadcaster RTS. "I'd never experienced such a rescue mission," added the fireman department chief.
The child and her family were apparently from German-speaking Switzerland and were on holiday in the alpine region, adds RTS.
According to a police spokesman cited by the paper, the girl was trapped in the hole from 11.45am to 2am the next morning, a more than 14-hour ordeal for the toddler.
The child was not hurt, according to reports. Initial reports suggest the accident was not related to the recent landslides in Moosfluh.