In the crystal structure of the acid platinum phosphate dipotassium di-μ-hydrogenphosphato-bis[aquaplatinum(III)](Pt—Pt), K2[Pt2(HPO4)4(H2O)2], the (Pt2)6+ dumbbells within the paddle-wheel complex show Pt—Pt distances of 2.4944 (5) and 2.4892 (5) Å. The pottassium ions are seven-fold coordinated by hydrogenphosphate groups. In the crystal, O—H⋯O hydrogen bonds help to establish the packing. The Raman spectrum was recorded.