In the last two decades, the lattice Boltzmann method (LBM) has emerged as a promising tool for simulating complex fluid flows. The method uses a uniform mesh spacing throughout the domain. Near solid boundaries, the resolution required to capture steeper gradients in flow variables can cause massive computational load due to the same mesh resolution being used everywhere else in the domain. This limitation is circumvented by using multi-block LBM in which finer mesh is used near the solid-fluid interface, whereas coarser mesh is used away from the solid boundaries. Consequently, multi-block approach requires exchange of data between the coarse and the fine grid at the interface at each time step. For two-dimensional flow problems like flow past a cylinder and flow in a lid driven cavity, the transfer of data between coarse and fine grid by using univariate splines has already been developed successfully. However, an efficient and accurate interpolation scheme in three-dimensional fluid flow simulation using multi-block LBM has not been demonstrated so far. This work employs a bivariate version of splines and devises an efficient algorithm for the solution of unknown coefficients. At the interface of the coarse and fine grid blocks, bicubic splines are constructed using the data on the coarse grid. The bicubic splines are subject to appropriate continuity conditions across adjacent splines and suitable boundary conditions. The resulting coupled equations in terms of the unknown coefficients are solved using a direct method without matrix inversion. The validation of the use of bicubic splines is done by solving flows around a three-dimensional cylinder and sphere with the help of multi-block LBM. Subsequently, the bicubic spline interpolation is employed for moving boundary simulation of a three-dimensional rigid hovering wing. The coefficients of drag and lift computed using multiblock LBM based on bicubic spline interpolation shows considerable reduction in noise compared to available results that use uniform mesh. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.