Background Gait and cognitive impairments are hallmark features of Parkinson's disease (PD) that significantly impact quality of life. These deficits arise from both dopaminergic and non-dopaminergic mechanisms, including cholinergic dysfunction. Transcutaneous cervical vagus nerve stimulation (tcVNS) is a non-invasive neuromodulatory technique that may enhance cholinergic function and has potential therapeutic relevance for individuals with PD. However, its feasibility, acceptability, adherence, and safety in a domiciliary setting remain unclear. We conducted a single-centre, double-blind, parallel, sham-controlled, randomised proof-of-concept study. Objectives The primary objective was to assess the feasibility, acceptability, adherence, and safety of home-based tcVNS. The secondary objective was to explore preliminary effects on gait and cognitive function. Methods Thirty-three participants with PD were randomised to either active (n = 16) or sham (n = 17) tcVNS and self-administered two stimulations twice daily for 12 weeks, followed by a 24-week post-intervention follow-up. Results Retention was high (93.9%), with two participants withdrawing from the sham group for reasons unrelated to the intervention. No serious adverse events were reported during the intervention period. Mild adverse events led to discontinuation of tcVNS use in three active and two sham participants. tcVNS had minimal effects on gait and cognition, although small, non-significant improvements in step length variability were observed. Conclusions This study represents the longest tcVNS intervention trial in PD to date and supports the feasibility, acceptability, and safety of domiciliary tcVNS. While preliminary findings suggest tcVNS may have therapeutic potential, larger trials are needed to establish its effectiveness for improving gait and cognitive function in PD.