When sourcing kids water shoes, prioritize breathable, quick-dry fabrics like Neoprene or Spandex mesh for the upper. These materials prevent waterlogging and reduce the risk of skin irritation. For the outsole, ensure it is made of Thermoplastic Rubber (TPR) or high-quality rubber with a non-slip lug pattern to provide superior traction on slippery pool decks or jagged rocks. Additionally, verify that the materials are BPA-free and Phthalate-free to comply with children's product safety standards.