BACKGROUND: Needle fear and vaccine hesitancy remain important barriers to widespread vaccination. We compared public preferences for two needle-free delivery platforms-nasal spray and high-intensity focused ultrasound transdermal vaccination-against conventional needle-and-syringe (N&S) administration. METHODS: Demographically representative online panels of adults in the United Kingdom (UK; n = 491) and United States (US; n = 500) completed multiple validated instruments: the Oxford Benchmark Scale for Rating Vaccine Technologies (OBSRVT, primary outcome measure), Oxford Needle Experience (ONE) scale and Oxford Vaccine Hesitancy Scale (OVHS). Preferences were assessed using the OBSRVT, stated willingness-to-pay (WTP), stated preferences, and two binary discrete-choice experiments (DCEs). Associations with needle and vaccine hesitancy were analyzed using the ONE scale and OVHS for quartile stratification with Cuzick's test for trend. RESULTS: Mean OBSRVT scores exceeded the N&S equivalence threshold (45) for both alternatives, with ultrasound highest (UK: 47.98 [95 % CI 47.07, 48.88]; US: 47.41 [95 % CI 46.35, 48.48]). Respondents were willing to pay a 25 % (UK) and 27 % (US) premium for ultrasound relative to N&S; corresponding premiums for nasal spray were 4 % and 8 %. In DCEs, each £/$25 price increase reduced the odds of choosing nasal spray by 30-40 %, but only 11-35 % for ultrasound, indicating lower price sensitivity for ultrasound. Increasing ONE scale quartile and OVHS pain subscale quartile were associated with increasing OBSRVT score and increasing WTP for nasal spray and ultrasound. CONCLUSIONS: Ultrasound-mediated vaccination is preferred over both nasal spray and N&S, particularly among needle- and vaccine-hesitant individuals. Needle-free technologies hold promise for improving uptake while streamlining logistics. This approach offers a transferable framework for de-risking emerging vaccine delivery platforms.