In hexagonal close-packed titanium, the symmetric tilt boundaries \([2\bar {1}\bar {1}0](01\bar {1}3)\) and \([2\bar {1}\bar {1}0](02\bar {2}1)\) have been studied by computer simulation using an embedded atom potential. The structure and energy of the boundaries under consideration have been calculated by method of molecular statics. The stability of the boundaries and grain-boundary self-diffusion coefficients have been calculated by molecular dynamics upon heating. It has been shown that the \([2\bar {1}\bar {1}0](01\bar {1}3)\) boundary is stable up to the hcp → bcc phase transformation temperature (1155 K), and the \([2\bar {1}\bar {1}0](02\bar {2}1)\) boundary, up to 900 K. It has been shown that the grain-boundary diffusion coefficients are close to experimental ones.