Coordination structures of implanted Fe, Co, and Ni ions were studied in 1.78–2.00-MeV 5 × 1016 ions/cm2-implanted silica glasses by x-ray absorption and optical absorption spectroscopies. It was found from x-ray absorption spectra that the implanted Fe, Co, and Ni ions are coordinated by ca.3 oxygen atoms. The implanted ions dispersed in glass matrix and did not form crystals. The valence of the implanted ions was about 1.5. The Fe–O, Co–O, and Ni–O interatomic distances were 190, 191, and 192 pm, respectively. In addition, it was found from optical absorption spectra that one-fifth of implanted Co ions were present as Co2+ ions in tetrahedral symmetry.