Great progress is being made on the use of axisymmetric ultrasonic guided waves in tubing for defect detection, classification and sizing. Benefits of excellent penetration and sensitivity to certain defects are possible. However, ultrasonic guided wave propagation and reflection in tubing is still not completely understood. For more comprehensive knowledge of ultrasonic guided waves in tubing, a study on non-axisymmetric modes cannot be avoided. A number of non-axisymmetric modes close to the axisymmetric modes on a dispersion diagram often makes it difficult to generate a single axisymmetric mode in tubing. Also, non-axisymmetric reflections occur due to non-axisymmetric defects, even for axisymmetric impingement. The purpose of this study is to explore the use of non-axisymmetric ultrasonic guided waves for both faster and simpler inspection as well as defect sizing analysis. As a result, it is hoped to optimize detection and screening via distance, incident angle, and frequency tuning.