As KAGRA is planning to join O3 in its later phase, a number of commissioning experiments are planned beforehand in order to bring the interferometer online as quick as possible in a tactical manner. We have so far successfully concluded two major commissioning experiments in 2018, that are the operation of the cryogenic Michelson interferometer and one-arm test with the X arm at room temperature. These tests assessed the readiness of a variety of hardware and software necessary for proceeding with the subsequent commissioning experiments. While we haven't found a major obstacle so far, we were able to identify critical components. In this talk, I will report on those commissioning activities together with latest status with the upcoming experiments towards participating in the terrestrial detector network during O3.