In the title coordination polymer, [La(2)(C(8)H(4)O(4))(3)(H(2)O)(2)](n), there are two independent La(III) atoms which are coordinated differently in slightly distorted penta-gonal-bipyramidal and slightly disorted bicapped trigonal-prismatic environments. The La(III) ions are bridged by μ(4)-isophthalate ligands, forming two-dimensional layers. In the crystal structure, these layers are connected by inter-molecular O-H⋯O hydrogen bonds into a three-dimensional network.