The densification of CaLa2S4 (CLS) powders prepared by combustion method was investigated by the use of Field-Assisted Sintering Technique (FAST) and Hot Pressing (HP). CLS powders were sintered using FAST at 1000 degrees C at different pressures and heating rates and sintered by HP under 120 MPa from 800 degrees C to 1100 degrees C for 6 hours with a heating rate of 10 degrees C/min. Comparison of both techniques was further realized by use of the same conditions of pressure, dwell time, and heating rate. Complementary techniques (XRD, SEM-EDS, density measurements, FTIR spectroscopy) were employed to correlate the sintering processes/parameters to the microstructural/compositional developments and optical transmission of the ceramics. Both sintering techniques produce ceramics with submicrometer grain size and relative density of about 99%. Nevertheless, HP is more suitable to densify CLS ceramics without fragmentation and also reach higher transmission than FAST. Transmission of 40%-45% was measured out of a possible maximum of 69% based on the Fresnel losses in the 8-14 mu m window when HP is applied at 1000 degrees C for 6 hours under 120 MPa. In both techniques, ceramics undergo reduction issues that originate from graphitic sintering atmosphere.