We investigated the effect of femtosecond-laser-induced surface modifications on ion incorporation into diamond crystals. The (001) surface of a diamond crystal was irradiated with femtosecond laser pulses. Boron ions were implanted on the laser-irradiated surface of two crystals: one at 600°C and the other at room temperature. The ion concentration along the depth of the crystal was measured with secondary ion mass spectroscopy. The concentration profile was parabolic, and in the deeper region after the peak, the ion concentration was higher in the irradiated area than in the nonirradiated area in both crystals. That is, the introduction of laser-induced surface modifications enhanced the ion migration along the depth direction. Transmission electron microscopy showed that the crystallinity of diamond was better in the crystal subjected to high-temperature implantation. These results support the idea that femtosecond-laser-induced surface modifications can enhance dopant incorporation into diamond while preserving the diamond’s crystallinity.