A tennis ball including a non-foamed thermoplastic core defining an internal volume. The core includes a thermoplastic material having a specific gravity of 0.86 to 1.38, a flexural modulus of 2.0 to 50.0 MPa, and a Shore D hardness of 10 to 70. A thickness of the thermoplastic material is between 3.0 and 8.0 mm. The thickness of the thermoplastic material is configured to maintain dimensional stability at internal pressures of between zero and 15 psi.