The removal of water vapor and carbon dioxide from gases is important in air separation, environmental protection applications, and some purifications. Zeolites are selective adsorbents for carbon dioxide, water vapor, and other impurities and are used in gas processing broadly. However, reliable data for coadsorption of carbon dioxide and water vapor are still largely lacking, as is knowledge of how adsorbed water influences mass transfer rates of carbon dioxide. This work provides a systematic experimental study on both equilibrium and mass transfer rates for water, carbon dioxide, and their binary mixtures in zeolites 5A and 13X. A volumetric apparatus was designed and used to measure adsorption isotherms over a wide temperature range, from -45 C to 175 C. Pure CO2 and water isotherms are described well by a multi-temperature Toth model. Binary data were measured at three different temperatures for three different water loadings. Mass transfer rates were measured by frequency response methods. A pressure-swing frequency response method (PSFR) was used to measure pure CO2 adsorption rates on both zeolites. The mass transfer mechanism is best described using a non-isothermal nanopore diffusion model. Water mass transfer rates were measured by a concentration-swing frequency response method (CSFR) and are described well by a linear driving force model. Binary diffusion of water and CO2 was studied by CSFR to investigate how the interactions between the molecules affect diffusion rates.