It’s one of the skills every diver should master, but one you hope you’ll never need to use—buddy breathing. This refers to sharing air with a partner on a dive to keep breathing if your air supply runs short. Also, if your equipment malfunctions while still getting to the surface safely.
There are two methods in use today, the older of which has started to be phased out in recent years. This old-school method of passing a shared regulator back and forth is what many seasoned divers learned during certification. Still, with the advent of the octopus, most divers now carry a backup regulator so that each diver can have its own air source when sharing.
First, indicate to your dive buddy that you are out of air or not getting air by slashing across your throat. Then, using the hand signals taught in your classes, you will convey the message “you, me, share air” to your partner. Your partner can then hand you or allow you to access their backup regulator.
Remain calm. Once you have a regulator in your mouth and are breathing again, you and your buddy should begin a controlled ascent to the surface. Following any deco stops, you would for whatever depth you were at when the mishap occurred. Keep hold of your buddy’s BCD, and they should also hold onto you. Staying in close contact is essential to maintaining airflow from your buddy’s cylinder.
This method has the advantage over the single regulator method in that each diver is always breathing versus having to pass an air source back and forth. If you are the buddy sharing your air with a companion, keep your eyes on your partner and help them remain calm.
If you ever find yourself in a shared air situation where two people are using one regulator, follow that canon of diving— don’t hold your breath. Slowly exhale while your buddy breathes before returning the regulator to you. Holding air in your lungs as you ascend can lead to lung damage. The person sharing their regulator should always hold onto it and pass it back and forth between themselves and their partner. Each diver should breathe for a count of two, then allow the other diver a turn.
For a simple demonstration, watch this video as these instructors execute the buddy breathing techniques on a dive to share air in and out of an air emergency.
