Previous research into volunteering has focused its attention on the differences between volunteers and non volunteers. However the tasks undertaken by different organizations and their volunteers are varied. The primary aim of this research was to identify the differences between two volunteer populations, Royal National Lifeboat Institute volunteers (N = 38) and Charity shop volunteers (N = 50). The participant’s personality dispositions were assessed using the International Personality Item Pool (IPIP, 2000) and the Sensation seeking scale –V (Zuckerman, 1994). Motivation to volunteer was assessed using the Volunteer Function Inventory (Clary, Snyder, Ridge, Copeland, Stukas, Haugen & Miene, 1998). RNLI volunteers were found to be significantly more emotionally stable than charity shop volunteers (f (1, 83) = 12, p < 0.001). They had a higher sensation seeking disposition overall (f (1, 82) = 9.01, p < 0.01) and specifically on the subscales ‘thrill and adventure seeking’ (f (1, 82) = 7.65, p < 0.01) and ‘disinhibition’ (f (1,82) = 12.75, p < 12.75, p < 0.001). RNLI volunteers were significantly motivated by the function ‘social’ (a desire and concern for interpersonal relationships) (f (1,84) = 5.03, p < 0.05). Finally, high emotional stability and disinhibition predict an increased likelihood of becoming an RNLI volunteer. It was concluded that RNLI volunteers have less anxiety manifestations, are high risk takers and are motivated by egoistic orientations. The differences found between the two volunteer populations cast doubt on whether it is viable for empirical research to approach ‘volunteering’ as a unitary concept as has been done in the past.