The National Institute for Health and Care Excellence (NICE) in the United Kingdom (UK) and the European Network for Health Technology Assessment (EUnetHTA), a network of HTA bodies, including the UK, offer manufacturers the opportunity to engage in early dialogue (ED) regarding specific evidence requirements for products in development. Recommendations inform evidence generation within and outside the clinical programme for future HTA product submissions. This review compares HTA ED processes offered by EUnetHTA and NICE, provides information on good quality interactions for manufacturers, and describes new service options introduced by NICE, including contingency plans should the UK leave the European Union (EU). A targeted review of literature and Internet-based sources identified the most recent information on ED processes provided by NICE and EUnetHTA. Both offer joint regulatory and HTA advice; this review focused on the HTA advice process. The EUnetHTA ED process involves the ED Working Party (EDWP) with agencies from France, Germany, Hungary, Italy, UK, Belgium, and The Netherlands; additional HTA bodies may participate in EDs as required. Manufacturers submit a briefing book with product and disease information, plus specific questions on clinical and economic issues for HTA. NICE employs a similar overall process and in April 2019 introduced different options, including an express service and choice of more limited expert review. EUnetHTA and NICE include the opportunity for face-to-face discussion plus written recommendations. NICE has published steps to ensure continuity of service if the UK leaves the EU. EUnetHTA and NICE ED services have similar process structures but differ in breadth of country feedback and flexibility of scope. The optimal time for seeking ED is preinitiation of main registration efficacy studies, aiding appropriate study design for HTA and regulatory review; alternatively, ED sought during study conduct informs the approach to economic analysis.