Everyone will need a visa except citizens of Switzerland and Israel.
Visas can be single entry or multiple entry, but multiple entry is recommended more than single entry. Multiple entry visas usually last a year, whereas the single entry last three months.
They cost $150 and take two days to process.
Other African cities and countries are accessible via boats and barges that travel infrequently along the Ubangui river. The Ubangui River flows into the Congo River, which is navigable all the way to Stanley Falls near Kinshasa/Brazzaville. Although slow, there are regular although adhering to no set schedule barges which travel from Bangui to Kinshasa/Brazzaville.