Tomu Sione was first elected to represent the constituency of Niutao in the House of Assembly of the GEIC in 1970. He was re-elected in the 1971 Gilbert and Ellice Islands general election, and in the 1974 Gilbert and Ellice Islands general election.
Tomu Sione first won a seat in the House of Assembly for Niutao in the GEIC in 1970. He was re-elected in both the 1971 and 1974 elections for the same constituency.