Primate tourism has been practised since the 1960s and growth has continued to this day. While the revenue created from primate tourism can be utilised for their conservation, negative effects such as disease transmission, higher levels of intragroup aggression and higher levels of stress and anxiety have been observed. Especially in endangered primates, effects of tourism should be studied to ensure primate tourism is beneficial. The endangered and endemic Zanzibar red colobus (Piliocolobus kirkii) at Jozani-Chwaka Bay National Park have been visited by tourists since the 1990s and visitor numbers to the park have reached nearly 60,000 per year. This study examines possible differences in behaviour between two groups with different tourist exposure. I collected data on self-directed behaviours, activity, movement and inter-individual spacing. Colobus monkeys showed higher rates of self-directed behaviour in the tourist group (8.29 ± 3.95 acts / hour) than in the non-tourist group (5.58 ± 3.91 acts / hour). Both group identity and the mean number of adult colobus within 1m of the focal animal were associated with higher self-directed behaviour rates. However, mean number of adult colobus within 1m of focal individual does not differ between the two groups and can therefore not be the sole reason for higher self-directed behaviour rates in the tourist-exposed group. Differences in group size, substrate use and tourist presence are likely reasons for the observed differences. There were no differences in activity budget or distance travelled during the focal observations between the two groups. This study provides valuable baseline data for future research on this heavily utilised for tourism but understudied primate species.