The February contract settled at 11.16 baht per kg, down from 11.20 baht, with the number of contracts traded falling to 16 from 27.
Trading was dull in line with the physical market due to the absence of overseas demand, brokers said.
However, prices would not fall significantly as the government is buying buy rice from farmers at higher-than-market prices to support domestic prices.
It said it would buy 5 percent paddy grade at 7,100 baht ($173.3) per tonne between November 1 and the end of February.
On the physical front, Thai 5 percent white rice was steady at 10.80 baht per kg.