We have studied the alpha-decay (AD) and spontaneous fission (SF) properties of the isotopes of Z=125, 126 and 127 superheavy nuclei. AD calculations have been performed over all the possible isotopes of Z=125-127 nuclei within the framework of Wentzel-Kramers-Brillouin (WKB) and Bohr-Sommerfeld quantization condition. To broaden the perspective of the calculations, we have also utilized from the analytic formula of Royer in the calculations of AD. In this way we believe that by using various approaches might be useful for the clarity of the predictions. Also, the SF half-lives have been computed by using formulae of Soylu and KPS. Decay modes for the isotopes are determined by using the results of different models. The decay modes obtained for Z=125 and Z=126 have been compared with the results of other studies, and α-decay chains have been presented for Z=127. Findings would provide opportunities for the future experimental researches.
