About 600kg of snow had been flown into Naha city from north-eastern Japan.
Reports say that residents expressed fears the snow had been contaminated in the wake of the crisis at the tsunami-hit Fukushima nuclear power plant.
But officials said the snow was from an area 400km (248 miles) from Fukushima and had undergone several safety tests.
The Fukushima Daiichi nuclear plant was badly damaged by the 11 March earthquake and tsunami. It is now in a state of “cold shutdown”.
“We explained that the snow was good to play with because we checked for contamination multiple times in Aomori and Okinawa, too,” a Naha city official is quoted as saying by the Reuters news agency.
Japan’s Mainichi Daily News reported that some of the concerned residents were evacuees from the Tohoku area, which was hit by the earthquake and tsunami last March.