Background: A decline in physical activity (PA) during pregnancy, despite its benefits to the mother and fetus, invites concerns for innovative platforms for its implementation. This cross-sectional study assessed knowledge, attitude, and “willingness to use” and “willingness to pay” for smartphone applications (apps) for PA. Materials and Methods: A total of 196 consenting pregnant women participated in this study. Eligible respondents were pregnant women who were 18 years and older, on at least a second antenatal visit and uses a mobile phone. Three purposively selected antenatal care facilities were surveyed. A self-developed questionnaire pilot tested for face and content validity was used as the research tool. Results: The mean age of the respondents was 27.5 ± 3.42 years, and 52% of them were occasionally engaged in PA. The point prevalence for smartphone use for general purpose and the usability rate of smartphone app were 72.4% and 84.2%, respectively. The rates for willingness to use PA apps for pregnancy and willingness to pay for the apps were 64.3% and 63.8%, respectively. There was a significant association between the attitude of respondents toward smartphone apps use for PA and number of parity (χ 2 = 7.119; P = 0.028). There was no significant association between knowledge of the use of smartphone apps for PA in pregnancy and each of the educational qualification (χ 2 = 13.046; P = 0.523), income (χ 2 = 11.086; P = 0.679), age (χ 2 = 4.552; P = 0.804), gravidity status (χ 2 = 5.302; P = 0.506), and number of parity (χ 2 = 1.878; P = 0.758). Conclusion: Nigerian pregnant women have good knowledge, positive attitude, and willingness to use smartphone apps for PA in pregnancy. There was a significant association between the number of parity and each of the attitude and knowledge of the use of smartphone apps for PA.