The concept of physical access to a single facility in a specific Research infrastructure (RI) has typically been the norm for transnational access (TNA) activities over the last decade. However, new and flexible approaches for providing access are required to allow RIs to deliver improved services that attract a wider range of users and stakeholders. WP6 addresses this need by designing and evaluating new mechanisms for accessing research facilities in the atmospheric domain of European RIs. In addition to physical access (in-person visit to a facility), both remote access (without a person visiting a facility) and virtual access (wide, free access provided through communication networks to resources and data that can be simultaneously used by an unlimited number of users) will be explored. These new access modalities and improved services will provide better support to users, allowing them to address key scientific questions and the related societal issues in a new way. WP6 will therefore provide additional options to the catalogue of services offered by the participating RIs and enhance their attractiveness with cross-RI services and opportunities not offered by single RIs. The enhanced access modalities will also facilitate cross-disciplinary research and technology development, while also fostering closer interactions between academics and industry.