When does co-op unlock? You unlock the co-op feature once you reach Emma's mansion. That will happen during the "Call the Cavalry" mission, around 20 to 30 minutes into the game (depending on your playstyle).
(PR) Dead Island 2 Co-Op Mode Explained, Cross-Gen Only and No Hosting for PS4 & Xbox One
EVERYTHING YOU NEED TO KNOW ABOUT CO-OP - Dead Island 2 is a great single-player experience, but it's fun to play with friends too as playing together has always been essential for our community. Co-op supports up to three players. You and your potential other two teammates have six characters to choose from, and your fellow co-op Slayers won't... well, shouldn't hurt you. So, let's dive into everything you need to know about co-op in Dead Island 2!
When does co-op unlock? You unlock the co-op feature once you reach Emma's mansion. That will happen during the "Call the Cavalry" mission, around 20 to 30 minutes into the game (depending on your playstyle). 
When does co-op unlock? You unlock the co-op feature once you reach Emma's mansion. That will happen during the "Call the Cavalry" mission, around 20 to 30 minutes into the game (depending on your playstyle).