Examples herein involve managing credit returns in a multi-source credit managed communication system. In examples herein, a first amount of slots of a credit managed destination are allocated for a credit managed source and a second amount of slots of the credit managed destination are allocated for a secondary source. Credit returns are controlled to the credit managed source based on the second amount of slots and in response to a value of a counter that tracks an amount of data sent from the secondary source to the credit managed destination, an amount of data sent from the credit managed destination, the credit returns providing an ability for the first source to send data to the credit managed destination.