When you become a certified Open Water 20 diver, a dive buddy is well worth searching for. Find three or more buddies who you feel comfortable to dive with. Then, if one of them can’t dive that day, the others may be available. The alternative is to dive with a dive center and/or club. Get to know the other divers there. It is a great way to meet and interact with like-minded divers with similar or better experience.
For first-time divers, speak to your instructor and/or dive center, and discuss dive buddies. There are always other divers who will be happy for you to join them. Make sure your first couple of dives are well within your comfort zone when diving with a new buddy.