Abstract: 3d mirror symmetry is a mysterious duality for certian pairs of hyperkahlermanifolds, or more generally complex symplectic manifolds/stacks. In this talk, I will describe its relationships with 2d mirror symmetry. This could be regarded as a 3d analog of the paper ’Mirror symmetry is T-duality’ by Strominger, Yau and Zaslow which described 2d mirror symmetry via 1d dualities.