The purpose of this study was to assess the bone speed of sound (SoS) through lifetime of a large Mexican population sample by determining the SoS from the radius and tibia using quantitative ultrasound (QUS). This is a cross-sectional evaluation of participants in the Mexican Health Workers Cohort Study. QUS measurements were performed using Sunlight Omnisense 8000P; Z- and T-scores were calculated for both sexes at the distal third of the radius and midshaft tibia, both on the nondominant side. A locally weighted regression smoothing scatterplot model was used to identify different phases of bone accretion and loss. A total of 9128 participants aged 1–75 yr were measured with QUS. Bone SoS accretion began 5 yr earlier in girls than boys (p < 0.05). Maximal SoS or peak bone SoS was noted at 28 yr in the radius and at 22 yr in the tibia. Postmenopausal women (45–50 yr) showed significant SOS decrease at both sites (p < 0.05) compared with men. Using the locally weighted regression smoothing scatterplot model, we found 5 different phases that constitute the biological development of bone over the life course, from ages 1–6, 7–12, 12–25, 25–50, and 50–75 yr (p < 0.05). Our study shows the age- and sex-dependent changes and different phases of bone development expressed by SoS measurements of the radius and tibia. The values reported in this study can be used as a reference for urban Mexican population.