This study investigates the impact of an innovative conservation action campaign called "Penguin Promises" implemented at uShaka Sea World in Durban, South Africa. Communication tools included interpretive signage, exhibits with and without animals, presentations, and personal interactions, along with a specially designed postcard, on which visitors could write a promise (pledge) to make a change in their daily lives to become more environmentally responsible. Visitors who completed a card were contacted a year or more after their visit and asked about the outcomes of their promise. The results (N = 316) showed that 49.4% of respondents could give an example of something positive they had done for the environment, that they attributed to the campaign. Based on the study, recommendations are provided for the design of effective visitor conservation action campaigns.