The Election Commission (EC) said only 4.18% of 2.12 million voters nationwide who had registered for the advance vote turned out to cast their ballots.
The percentage could not match the previous advance voting in 2008 when 26.30% of 2.09 million voters went to the stations.
Si Sa Ket topped the advance voter turnout at 30.55% followed by Surin at 29.34%, EC deputy secretary-general Somsak Suriyamongkol said. Seven provinces - Krabi, Rayong, Chon Buri, Samut Prakan, Surat Thani, Samut Sakhon and Nonthaburi - found less than 2% of voters went to the polling station, he added.
The advance voting ended at 3pm after all stations opened at 8am on Sunday.
The full senate poll will be held on March 30 for voters to select 77 senators to represent 77 provinces.
EC secretary-general Puchong Nutrawong pointed to political uncertainty as a possible reason for the low turnout in the advance voting.
"This advance voting is somewhat quiet probably because of the present political situation. The ruling of the Constitution Court, which says the general election was in violation of the constitution, could have dampened voters' eagerness to come out to vote," he said.
EC chairman Supachai Somcharoen said no attempts to block voters were reported to the agency.