British Army basic training (BT) and initial trade training (ITT) enable personnel to develop role‐related physical capability to perform in‐service job‐roles. The study aimed to compare physical performance of trainees (completing ITT) and trained soldiers, on a series of gym‐based fitness tests and representative military tasks. A total of 316 British Army personnel [68 trainees (63 men: 22 ± 3 years, 71.6 ± 8.4 kg and 1.74 ± 0.07 m) and 248 trained soldiers (225 men: 27 ± 6 years, 78.7 ± 12.7 kg and 1.76 ± 0.08 m)] completed two sessions. Session 1; body mass, stature, age and gym‐based tests (2 km run, broad jump, seated medicine ball throw, hex bar deadlift, 100 m shuttle sprints, pull‐ups and mid‐thigh pull). Session 2; representative military tasks (loaded carriage [stage 1, 4 km, 35–40 kg and 4.8 km h−1 fixed pace and stage 2, 2 km, 20–25 kg and individual best‐effort speed], tactical movement, casualty drag, stretcher carry, vertical lift, repeated carry and incremental lift). Independent sample t‐tests were employed to examine group differences. Compared to trainees, trained soldiers were older (p < 0.001), heavier (p < 0.001) and scored higher on broad jump (p = 0.024), medicine ball throw (p = 0.007) and mid‐thigh pull (p = 0.048), but were slower on 2 km run (p = 0.047), loaded carriage (p < 0.019), tactical movement (p < 0.001) and casualty drag (p < 0.001). Overall, trainees achieve higher scores on aerobic/anaerobic tests, whereas trained soldiers outperform trainees in strength/power‐based tests. Although a cross‐sectional comparison does not provide strong evidence, the results may indicate that cardiovascular fitness is developed during BT, whereas muscle strength/power develops post BT/ITT. These findings would need confirming by a longitudinal study and could inform the development/management of role‐related fitness during BT, ITT and through career.