This conference report summarizes the contributions to, and discussions at the joint meeting of the 9th Asia Pacific-Transport Working Group (APTWG) & EU-US Transport Task Force (TTF) workshop held online, hosted by Kyushu University, Japan, during 6–9 July 2021. The topics of the meeting were organized under five main topics: (1) isotope effect on transport and physics on isotope mixture plasma, (2) turbulence spreading and coupling in core-edge-SOL, (3) interplay between magnetohydrodynamic topology/instability and turbulent transport, (4) interaction between energetic particle driven instability and transport, (5) model reduction and experiments for validation.