The obvious day trip from Kourou is the Îles du Salut, covered in Things to Do — it is close enough to reach easily and deserves a full day rather than a brief visit. Most visitors to Kourou who are short on time prioritise the space centre and the islands over anything else, and that combination fills two days comfortably.
The rainforest interior of French Guiana is accessible from Kourou, though the serious jungle destinations — the Saül highlands, the upper Maroni river — require more than a day trip. Tour operators in Kourou and Cayenne run guided pirogue trips on the Kourou River, which passes through intact lowland jungle and offers good birdwatching. These can be arranged as half-day excursions from town.
Cayenne, the capital, is an hour away by road and worth visiting for its Creole architecture, covered market (Marché du Vieux Fort), and the better restaurant scene. It's a straightforward day trip by taxi collectif.
