The aims of the study were (1) to assess the reliability of transabdominal (TA) and transperineal (TP) ultrasound during a pelvic floor muscle (PFM) contraction and Valsalva manoeuvre and (2) to compare TA ultrasound with TP ultrasound for predicting the direction and magnitude of bladder neck movement in a mixed subject population. A qualified sonographer assessed 120 women using both TA and TP ultrasound. Ten women were tested on two occasions for reliability. The reliability during PFM was excellent for both methods. TP ultrasound was more reliable than TA ultrasound during Valsalva. The percentage agreement between TA and TP ultrasound for assessing the direction of movement was 85% during PFM contraction, 100% during Valsalva. There were significant correlations between the magnitude of the measurements taken using TA and TP ultrasound and significant correlations with PFM strength assessed by digital palpation.