Adventurous Training (AT) within Army Phase One organisations is used to assist in the development of British Army recruit core values . This study measured the internalisation of British Army recruit core values during the AT week at two separate Phase One training organisations. A pre-test, post-test design was used to evaluate recruit (n = 302) motivational internalisation of core values during a structured 5-day training week, where recruits undertook a mixture of rock climbing, caving, canoeing, kayaking, and hill walking activities, and were required to complete tasks in unfamiliar and challenging environmental conditions. Reflecting the influence of the training, Bonferroni corrected, pair-samples, ttests conducted on the Relative Autonomy Index were significant for the motivational internalisation of All core values and four of the six independent core values (Selfless Commitment, Courage, Loyalty and Respect for Others). Further examination at external, introjected and integrated regulations additionally revealed significant results for all core values with the AT week appearing to have the most robust effect on introjected regulation. A second hypothesis was concerned with the effects of the leadership of AT instructors in developing recruit core values and asked specifically whether high levels of transformational leadership behaviours were associated with an enhanced internalisation of core values. Fifty nine instructors took part in the study and four transformational leadership behaviours were hypothesised to be associated with greater gains in the internalisation of all core values. Analyses revealed mixed results regarding individual transformational leadership behaviours; however, individual consideration was found to be the most significant behaviour. The implications for training developments are discussed.