Lead free antiferroelectric materials are the focus of much attention for the replacement of lead based materials in electronic devices, such as high energy storage capacitors, sensors, actuators. In this study, we present first lead free perovskite-like layer structure antiferroelectric material, strontium tantalum lanthanum titanate. The thermal variation of dielectric permittivity and dielectric loss indicate phase transitions from an antiferroelectric to a ferroelectric and finally to a paraelectric on heating. Using high resolution neutron diffraction, this study aims to establish accurate crystal models for the three phases and the relationship between them.