To derive UV escape fractions for primordial galaxies, we perform three-dimensional radiative transfer calculations using high-resolution hydrodynamic simulations that include supernovae feedback. As a result, we find that protogalaxies can be highly ionized by intense UV radiation from young stars, and hence have large escape fractions (> 15%). The escape fraction decreases with the chemical evolution of the protogalaxy because of dust extinction.We also study the infrared properties of protogalaxies resulting from chemical evolution. Interstellar dust effectively absorbs UV radiation from stars and then radiates it as infrared. The infrared radiation of high-z galaxies is shifted to submillimeter wavelengths by cosmological redshifts. Hence, they can be promising targets for ALMA. We show the surface brightness distributions of protogalaxies at submillimeter wavelengths and discuss prospects for their detection.