Abstract: An underwater pile-framed structure comprises a plurality of upright piles 11 arranged in two parallel and spaced rows, reinforcing cages 13 surrounding the piles in peripherally spaced relationship thereto, and precast block stacks 22, 23 connecting together the piles in the two rows and surrounding individual pile-cage assemblies in each row. The piles are driven into the seabed in two spaced and parallel rows, the reinforcing cages are lowered over the piles to predetermined positions, the blocks are stacked over the cages to connect together the pile-cage assemblies in the two rows, and concrete is poured into the annular clearances between the piles and the block stacks.