If a diver signals 'Low on air,' what is the most appropriate action?

When a diver signals 'Low on air,' sharing air with a buddy is the most appropriate action because it helps maintain safety and ensures both divers can ascend together. In a buddy system, divers are trained to monitor each other's air supplies, and sharing air allows both to remain underwater longer while managing the situation effectively.

By sharing air, divers can safely execute a controlled ascent, which reduces the risk of problems such as decompression sickness that could occur if someone ascends quickly without decompressing properly. It is essential that both buddies communicate clearly during this process and practice proper air-sharing techniques, such as using the alternate air source or buddy breathing.

Continuing to dive as planned could lead to dangerous situations if air supply runs critically low before reaching the surface. Ascending immediately without a plan or proper coordination with a buddy can also lead to dangerous situations, including rapid ascent, which is not advisable without proper safety stops. Signaling a dive master for help could be appropriate in some circumstances, but immediate action to share air is typically the most direct and effective response to a low air signal.