What is the recommended maximum length for a snorkel for optimal use in diving?

The recommended maximum length for a snorkel for optimal use in diving is 15 inches. A snorkel that is around this length provides a balance between allowing easy breathing and minimizing the effort required to clear water from the snorkel. When snorkels are longer, they can create additional resistance and make it more difficult to breathe comfortably, particularly when submerged.

Optimal snorkel design also includes features such as the angle of the mouthpiece and the diameter of the tube, and a 15-inch snorkel typically offers a good compromise for most divers between comfortable usage and efficient breathing. Longer snorkels may lead to discomfort or a higher risk of fatigue during extended use while diving.