We have measured the isotope shifts of 87 transitions in Sm II in the 418–465 nm spectral region and the magnetic-dipole and electric-quadrupole hyperfine constants of 13 low-lying even-parity metastable levels and 76 odd-parity levels. These results will be immediately applicable to stellar spectroscopy.PACS Nos.: 32.30.–r, 32.10.–f