Sodium stannate trihydrate is primarily used as a source of stannate ions in alkaline electroplating baths for tin and tin alloys, promoting uniform, smooth, and corrosion-resistant metal deposition, especially in electronics and metal finishing industries.

It serves as an intermediate in the production of organotin catalysts for polymerization reactions.

In the textile industry, it acts as a mordant to improve color fastness in dyeing and printing processes.

In ceramics and glass manufacturing, it functions as a flux or stabilizer to modify surface properties, enhance durability, and improve strength and stability in refractory materials.

Additionally, it is employed in corrosion inhibitors for metals in industrial cooling systems and as a component in flame retardants for certain materials.

It is also used in wastewater treatment to precipitate heavy metals, such as lead and tin, aiding in pollution control.