The Congo flows mostly west from Kisangani just below the falls , then slowly bends southwest , passing by Mbandaka , joining with the Ubangi River , and running into the Pool Malebo ( Stanley Pool ) . The Congo flows generally northwards from Kisangani just below the Boyoma falls , then gradually bends southwestwards , passing by Mbandaka , joining with the Ubangi River , and running into the Pool Malebo ( Stanley Pool ) .