After receiving many questions about the differences among masks for snorkeling, scuba diving, and free diving, I decided to take this opportunity to explain why the prices of masks differ. Many people find prices in the big shopping center much cheaper. It costs only about NT$ 400 to NT$500 for a set of masks and snorkel. On the contrary, a mask that a diving coach recommends usually costs more than NT$1,000. How to explain the differences? The key reason lies in the demand for use.

The most inexpensive is the mask for snorkeling. Many parents will take their children to the beach in the summer and they will buy masks from local shops. These are for temporary use and can be discarded easily. In addition, snorkeling is mainly carried out on the surface of the water, so there is no need to use a mask designed for deep underwater. Accordingly, the mask for snorkeling is only for a few-time usage. It does not require materials as durable as that for other types of diving. Neither does it need to be water pressure resistant. This explains why the quality and the material for snorkeling masks are not as good as others. 

The most obvious difference between snorkeling mask and mask for underwater diving is the lens. A  diving mask sues high-transparency tempered glass, while the inexpensive snorkeling mask uses PC plastic lenses. The big difference in materials accounts for the price discrepancy. For long-time usage, it is recommended to purchase a mask that is well-made, comfortable, and a good fit for your face.​

What is the difference between a mask for scuba diving and a mask for free diving? In comparison, the most significant difference is the volume ratio of the interior of the mask.

One of the purposes of diving activities is to experience beautiful underwater scenery with our own eyes. The mask needs to be resistant to water pressure and the lenses can provide a good field of view in the water. The Mask lens for scuba diving is generally larger. Single-lens design can avoid sight interference in the middle of the nose bridge. It is a common design for scuba diving masks. In addition, for a convenient check on the dive watch, the vertical design of the mask glass will be slightly extended downward, so that it is easy to look at the watch with the corner of one’s eye.

For freediving, one does not need to bend his or her neck to check on the watch, so most of the masks for free diving are double lenses, and the lens will be as close to the eye as possible. The closer the eye is to the center of the nose, the larger the field of view as the sight interference is minimized. In addition, the internal volume of the mask lens is reduced. This type of mask is called a “low volume mask”.

The smaller the internal volume of the mask, the less air is used to balance water pressure. A low-volume mask is crucial, especially when there is little air left in the lungs. As the internal volume is small, the size of lens will be smaller as well and is streamlined to reduce resistance encountered when traveling in the water. In contrast, the lens for scuba diving may not have a streamlined design since the purposes are comfort wear and to broaden the field of view. A freediver who uses a scuba diving mask will encounter greater resistance and consume an excessive amount of air when balancing water pressure.

Of course, depending on individuals, free diving masks can also be used for scuba diving, but the comfort level will be reduced. Theoretically, a scuba diving mask works as a free diving mask within 20 meters of water depth because such depth does not require a high volume ratio. A regular double-lens mask has a volume between 230-275, while a single-lens mask with a wide field of view has a volume between 250-350. The volume must be less than 220 to be counted as a free diving mask. If you want to have a mask that works for both scuba diving and free diving, a scuba diving mask with a smaller volume can be used for free diving as long as the dive does not exceed a depth of 20 meters. Overall, it is recommended to choose one’s mask according to needs. 

For fun and smooth diving experiences, purchasing masks according to your real needs is highly recommended!