To join Retrosub, please send an email to Mario at retrosub@yahoo.com. Please tell him a little bit about your background and why you'd like to join the list.

The RetroSub Freedivers are a loose band of underwater hunters, gatherers and sightseers who seek to relive the halcyon days of underwater exploration by using primitive, historical, or in other ways inadequate equipment. RetroSub is based in the San Francisco Bay Area, but membership is open worldwide.
Being a member of the RetroSub Freedivers doesn't necessarily mean you always dive "retro". There are plenty of us who own modern (Yamamoto) wetsuits and will wear nothing else. Some of us are tech-heads, eagerly awaiting the next technological breakthrough that will make freediving or spearfishing even better. What bands us together is a deep feeling for history and the willingness to occasionally use antediluvian equipment to experience it first hand.
RetroSub is a club for freedivers, which means we eschew the use of SCUBA in favor of breath-hold diving. Those of us that hunt believe in taking only what we need from the ocean and nothing more. We are an environmentally aware, ecologically conscious, and ethically sound group of individuals. This is not to say that we are Politically Correct; you may find us engaging in some SCUBA bashing from time to time.