Abstract The next-generation experiment JUNO will determine the solar oscillation parameters - sin 2 θ 12 and Δ m 21 2 - with great accuracy, in addition to measuring sin 2 θ 13 , Δ m 31 2 and the mass ordering. In parallel, the continued study of solar neutrinos at Hyper-Kamiokande will provide complementary measurements in the solar sector. Here we address the expected sensitivity to non-universal and flavour-changing non-standard interactions (NSI) with d-type quarks from the combination of these two future neutrino experiments. We also show the robustness of the measurement of the solar parameters and sin 2 θ 12 and Δ m 21 2 in the presence of NSI and comment on the enduring potential viability of the LMA-D solution.