People may not take protective action (e.g. use condoms) either because they have no intention to engage in the protective behaviour, or because they have the appropriate intention but are unable to act upon it. This paper examines variations in intentions to use condoms for vaginal intercourse with main and casual partners as a function of gender, ethnicity and risk. Additionally, the paper examines the extent to which these different factors influence the degree to which people can (or cannot) act upon their intentions. While 68% of men and 81% of women report intentions to use condoms for vaginal sex with their casual partners, only 33% of men and 37% of women intend to use condoms for vaginal sex with their main partner. Men with positive intentions were able to carry out those intentions about 64% of the time with respect to both main and casual partners; women with positive intentions were able to act upon these intentions 53% of the time with their main partners, but almost 82%, of the time with their casual partners. Possible factors influencing the ability to act on one's intentions are explored and implications for interventions are discussed.