Champlain Sea clay, a sensitive marine clay, is commonly found along the Saint Lawrence River basin in Eastern Canada. According to recent studies, cement is efficient in treating Champlain Sea clay. However, there is no information available regarding the tensile strength of cement-treated Champlain Sea clay. This paper presents an experimental investigation on its tensile strength using two indirect testing methods: the Brazilian tensile strength (BTS) test and the unconfined penetration (UP) test. The study shows that both the BTS test and the UP test can be easily implemented to study the tensile strength of cement-treated Champlain Sea clay. Compared to the UP test, the BTS test is recommended in future studies for its more consistent test results and more uniform sample failure modes. The tensile strength was correlated with the unconfined compressive strength (UCS) of cement-treated Champlain Sea clay. Based on the BTS test results, the tensile strength can be estimated at approximately 7% of its compressive strength for cement-treated Champlain Sea clay.