During the PADI Open Water Diver course, students are taught to manage many emergency situations including running out of air. In a previous post, we talked about the CESA, when can’t get assistance from another diver.

Today we look how to teach the alternate air source skill with help from your dive buddy.

This exercise is thoroughly practiced during the PADI Divemaster course and the Instructor Development Course (IDC).


The most commonly used alternate air source during a PADI Open Water Diver course is the octopus. And this is what we are focusing one here.

Other possibilities include a regulator second stage mounted on the BCD low pressure inflator and a pony bottle. In any case, the alternate air source should be located in the triangle between the chin and the lower corners of the rib cage. And be conspicuously marked, for instance yellow.

Confined Water Practice

Air sharing in introduced early in the PADI Open Water Diver course.

During Confined Water Dive 1 in shallow water, students must breathe effectively from an alternate air source provided by another diver for at least 30 seconds. They can practice on their PADI Instructor, however for learning purposes, I recommend to have them perform the skill on each other so they can act as donor and receiver.

During Confined Water Dive 3, the students will share once again but this time for 1 minute, while swimming and then surface. The receiver will inflate their BCD orally. The standards state they must both act as donor and receiver.

The video shows IDC candidates how to demonstrate the skill in shallow water.

Hand signals play a crucial role in this exercise as communication is key when managing an emergency.

The “out of air” signal can be given before or after securing the air source as breathing is the priority.
Next comes the “OK” signal. The donor should make sure that the receiver is now breathing comfortably. Once that is established, both divers agree to end the dive and ascend by giving the “up” signal.


For demonstration purposes, the Divemaster or Instructor can give the “30 seconds” signal during air sharing or once the demo is over.

Other critical attributes for this skill are:

  • Bubbles when regulator is out
  • Regulator right side up
  • Roman hand shake
  • Ascent simulation

During the PADI Skill Circuit, Divemaster trainees and IDC candidates wanting to become PADI Instructors will practice this skill in a stationary position and also while ascending.

Open Water

Practicing the use of the alternate air source is part Open Water Dive 2.

Once again, the students must act as donor and receiver in a stationary position but without a minimum time requirement.

They must also ascend using the alternate air source while acting either as donor or receiver.

The most efficient way to organize both these exercises is too have the students perform the skill once during the dive and again at later with different roles while ascending. This will mark the end of Open Water Dive 2

You can watch more skill demonstrations on our YouTube Channel.

Please message me if you have any questions.


Guillaume Fargues

PADI Course Director #482749

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