I mostly travel alone, because I am alone. I have fun meeting new people that way. But, from time to time I do get together with a group of friends and take a dive trip.
It depends upon the type of diving that I will be doing. If I’m planning on doing the deeper, more complex stuff then I prefer to have other divers who I know and trust to dive with. If I’m just out to see the reef or do shallow recreational; then usually I go alone and hook up with other divers who I might not know.