Surface anthropometric measures are commonly used to assess body composition in trained individuals. Standardised pre-test guidelines (morning, fasted) present logistical concerns. The impact of daily activities on skinfold (SKF) assessment has been established in males; however, there is a lack of research examining females. The aim of this study was to assess the within-day agreement between standardised and non-standardised surface anthropometric measures in trained females. Measures including body mass, eight SKF and six circumferences were collected by an International Society for the Advancement of Kinanthropometry level 1 anthropometrist on forty trained females (twenty naturally menstruating and twenty using a contraceptive) under standardised conditions (morning, fasted, rested and hydrated) and non-standardised conditions (9–10 h later after free-living) on the same day. The menstrual or contraceptive pill phase was not controlled for. The intra-class correlation coefficient and typical error were calculated to assess reliability. Overall group means were compared to assess if a significant change occurred. The sum of eight SKF sites (∑8 SKF) displayed excellent reliability, and no significant difference was noted between conditions. Greater levels of disagreement were represented by those with ∑8 SKF > 136 mm. Significant differences in group means were recorded for body mass and waist circumference. All other five circumference sites remained unchanged throughout the day. Findings suggest that if accuracy is required, body mass and waist circumference should be collected in a standardised state. SKF and all five other circumferences can be collected in trained females at any time of day without considering pre-test standard guidelines.