WikiBubbles
Wikibubbles is an global community of bubblers (scuba divers, freedivers, and snorkelers) dedicated to exploring the ocean safely and confidently. Bubblers help each other discover hidden gems, plan the perfect trip, and share their passion for the underwater world by adding a site, sharing a review about a site, add a dive log about a site.
How to join
This community requires an application. Apply through their site to join — the process helps keep discussion quality high.
Features
Related communities

r/scuba
111,000 membersWelcome to /r/scuba where scubbits dive deep! Ask questions and trade tips with a diverse community of divers, from open water newbies to dive instructors, commercial divers and scientists from around the world. Share your stories, pictures and video to have discussions with a subreddit full of people who love the underwater world and dream fishy dreams. Please read the sidebar and widgets! What are you waiting for? Come on in, the water is nice!

Divers Around the World
71,504 membersMeet other divers around the globe and share your dive knowledge.

Scuba Board
50,000 membersScuba Board is an online forum community for scuba divers with discussion boards, trip planning, dive site reviews, equipment advice, and certification information.
PADI Community
50,000 membersOfficial PADI Scuba Diving certification organization with training resources, diver directory, and community forums.