Background: Erectile dysfunction is a highly prevalent consequence of pelvic cancer treatment in males. For erectile dysfunction that is refractory to pharmacological intervention, surgical implantation of a penile prosthesis offers a more definitive treatment option. In this paper, we aim to assess patient decision satisfaction and regret levels amongst pelvic cancer patients who subsequently underwent penile prosthesis implantation, as there is a lack of data available amongst this patient cohort. Methods: A cross-sectional telephone survey was administered to men who underwent implantation of a penile prosthesis at a single tertiary andrology centre between December 2023 and May 2025. The survey purported to assess specific aspects of the post-prosthesis implantation experience, including cosmesis and ejaculatory function, as well as overall decision satisfaction and regret. Demographics were collected from medical records, and responses were analysed using simple data analysis and Fisher’s Exact Tests. Results: Eighteen men were identified who had developed erectile dysfunction secondary to pelvic cancer treatment and had subsequently undergone implantation of a penile prosthesis (mean age 62, mean Body Mass Index 28.9). Overall, 72% of patients were either “Happy” or “Very Happy” with their procedure, with only one patient stating that they would “Probably Not” undergo the procedure again. A significant association was identified between increased patient age and reduced decision satisfaction levels (p = 0.0294). Conclusions: Implantable penile prosthesis is generally a well-tolerated procedure amongst the male pelvic cancer patient cohort, with high overall decision satisfaction rates. This permits more informative pre-operative counselling allowing prospective patients to make more informed treatment decisions, and may provide greater confidence for patients worried about how treatment could affect their sexual function.