COSINE-100 is a direct dark-matter (WIMP) search experiment that uses an underground array of low background NaI(TI) scintillating crystals as a target/detector in the Yangyang deep underground laboratory. In spite of the underground experimental environment, the detector array and surrounding materials still contain some radioactive nuclides that were primarily produced by previous exposures to cosmic rays. Studies of the time-dependent contamination levels of these cosmogenic radioactive isotopes are required in order to understand these backgrounds to rare event search experiments. In this presentation, results of studies of cosmogenic nuclide contaminations in the COSINE-100 detector materials and comparisons to MC simulations will be presented.