Scuba Diving in Saltwater vs Freshwater: 10 Key Differences You Need to Know Of

When most people think of scuba diving, they imagine exploring the turquoise waters of tropical beaches. However, the underwater world is not limited to the ocean. In fact, many divers enjoy freshwater diving in locations such as lakes, rivers, and quarries.

Scuba diving in saltwater vs freshwater offer vastly unique experiences in terms of underwater visibility, buoyancy, marine life, currents, water temperatures, site diversity as well as dive equipments.

Whether you’re a seasoned diver or just starting, understanding the nuances of freshwater and saltwater diving can make a big difference in helping you choose your next dive destination. In this article, we will explore the major differences between the two and how they affect your diving experience.

1. Buoyancy

The key difference between freshwater and saltwater diving is the effect of buoyancy on the diving experience. Due to the differences in salinity, the buoyancy in saltwater is significantly higher than in freshwater. This means that divers will need to adjust their buoyancy control techniques accordingly when transitioning from one environment to the other.

In saltwater, divers will typically need to wear more weight to counteract the increased buoyancy, while in freshwater, they may need to wear less weight. Additionally, the different densities of saltwater and freshwater can affect the way you move and navigate underwater.

Saltwater divers may find it easier to swim and maneuver due to the increased buoyancy, while freshwater divers may find themselves sinking more easily and need to use more effort to move around. Freshwater diving generally require divers to have a stronger grasp on buoyancy control so in terms of beginner friendliness and ease of buoyancy control, saltwater diving is more beneficial than freshwater diving.

2. The Physical Differences Between Freshwater and Saltwater

One of the primary differences between freshwater and saltwater is their composition. Saltwater has a higher concentration of salt, which makes it denser than freshwater. As a result, saltwater exerts more pressure on your body than freshwater when you are diving. As mentioned earlier, this difference in density can affect your buoyancy, making it easier to float in saltwater than in freshwater.

Another physical difference is the presence of waves. Saltwater has more waves on the surface than freshwater, which can impact your diving experience. Waves can make it more challenging to maintain your balance and control your movements especially when you’re ascending to the surface for rest stops.

3. The Biological Differences Between Freshwater and Saltwater

Freshwater and saltwater have different ecosystems, which means that the plants and animals that live in them are different. Thi difference in biological diversity can affect your diving experience. Diving in saltwater gives you the opportunity to see a wide variety of marine life. Freshwater diving, on the other hand, may be less exciting in this regard.

Flora

In saltwater, you’ll find a wide variety of marine plants, such as coral reefs, kelp forests, and seagrasses. These plants are essential for maintaining the delicate balance of the marine ecosystem, providing shelter and food for a range of marine animals.

In freshwater environments, you’ll find a different set of plants, such as water lilies, duckweed, and cattails. These plants are adapted to the lower salinity levels and different nutrient levels found in freshwater environments.

Fauna

In saltwater, you’ll find a diverse range of marine animals such as colorful tropical fish, sharks, rays, dolphins, and sea turtles. These animals have evolved to live in a saline environment and have adapted unique strategies to survive in the ocean’s harsh conditions. For example, some saltwater fish have specialized organs to regulate the amount of salt in their bodies, while others have developed camouflage techniques to avoid predators.

In contrast, freshwater environments are home to a different set of animals, such as catfish, trout, and crayfish. These animals have adapted to live in freshwater, which has different physical properties than saltwater. Freshwater fish, for example, do not have to deal with the same osmotic pressures as their saltwater counterparts, and many have evolved to tolerate colder temperatures and lower oxygen levels.

4. Visibility Differences Between Freshwater and Saltwater

Visibility is another key difference between freshwater and saltwater diving. In general, saltwater environments tend to have better visibility than freshwater environments. This is due to a variety of factors, including the fact that saltwater is denser than freshwater, which means that light travels through it more easily.

In addition, saltwater environments often have a higher concentration of plankton, which can reduce visibility. However, in many cases, the clearer water and greater visibility ranging from 30 to 100 feet or more in clear saltwater environments.

In contrast, freshwater environments can be murkier and more difficult to see in with visibility ranging from just a few feet to 30 feet or more. This is due to factors such as sediment, algae, and plant matter in the water. However, some freshwater environments can still offer good visibility, particularly if they are well-maintained or if visibility is enhanced through the use of artificial lighting or other techniques. For example, the watery ghost town of Capo d’Acqua Lake in Italy offers crystal clear underwater visibility.

5. Difference in Currents

In general, saltwater environments are more prone to strong and unpredictable currents, which can pose a significant challenge to divers. These currents can be caused by a variety of factors, including tides, wind, and temperature differences. Divers in saltwater environments need to be skilled at navigating these currents and master the art of horizontal gliding underwater to minimize physical exertion caused by these currents.

On the other hand, freshwater environments are generally less affected by currents, making diving in these environments less challenging in this regard. However, there can still be some mild predictable currents present in freshwater environments, such as those caused by the flow of a river or underwater springs.

6. The Effect of Temperature on Freshwater and Saltwater Diving

Another significant difference between freshwater and saltwater diving is the temperature. When it comes to diving, the temperature of the water can affect the amount of thermal protection you need to stay comfortable and safe as well as the rate of your air consumption underwater. As a general rule, saltwater is often warmer than freshwater, with the average temperature of saltwater typically ranging between 55-85°F (12-29°C).

Most popular saltwater dive destinations are located in moderate tropical regions where you won’t need thick wetsuits (you can even dive without a wetsuit) for scuba diving. Generally 3mm wetsuits are enough for recreational diving in salt water destinations no matter the time of the year.

But if you’re diving in freshwater, keep in mind that the temperature can change a lot depending on the season. During spring and autumn, the water temperature may be cooler than in the summer, so a thicker wetsuit with a minimum thickness of 5mm may be needed to stay comfortable and safe. In the summer months, a thinner wetsuit with a minimum thickness of 2mm may be sufficient.

7. The Impact of Depth on Freshwater and Saltwater Diving

Diving in freshwater and saltwater can also differ in terms of depth. In freshwater, the maximum depth is usually around 40 meters, while in saltwater, it can go up to 200 meters or more based on your experience and diving certification. Deeper dives in saltwater can be more challenging because of the increased pressure, and divers need to be careful about their descent and ascent rates to avoid decompression sickness.

8. The Impact of Salinity on Freshwater and Saltwater Diving

The salinity of the water can also have an impact on your diving experience. Saltwater has a higher salinity level, which can make your body lose more water and electrolytes through sweating. This can lead to dehydration, especially during long dives. So you might need to surface more frequently or you can even become crafty and drink underwater without needing to resurface at all.

Freshwater has a lower salinity level, so you may not need to hydrate as often during your dive. Generally pre diving hydration is enough for your freshwater entire dive session.

9. The Equipment Needed for Freshwater and Saltwater Diving

While some equipment is necessary for both types of diving, there are specific items that you may need for one but not the other.

Common equipment for both freshwater and saltwater diving includes a mask, fins, regulator, buoyancy control device (BCD), and a tank of compressed air. However, saltwater divers may need a heavier weight belt to offset the increased buoyancy of saltwater.

Another consideration for both types of diving is exposure protection. Divers may need to wear a wetsuit, drysuit, or a dive skin depending on the water temperature. In general, saltwater is warmer than freshwater, but there are exceptions depending on the location and depth of the dive.

In addition to these basic items, there are other pieces of equipment that may be necessary depending on the specific dive. For example, a dive computer needs to be specifically calibrated to specific algorithms based on whether you’re diving in saltwater or freshwater for it to accurately measure pressure changes and correspond it to diving depth.

10. Wreck Diving in Saltwater vs Freshwater

Saltwater environments tend to have more wrecks and underwater structures compared to freshwater due to their greater depth higher volume of maritime traffic in oceans and seas compared to rivers and lakes. The deeper waters of the ocean make it possible for larger vessels to travel and, unfortunately, accidents happened in the past and still happen. Over time, these wrecks become artificial reefs and provide habitat for a variety of marine life, making them popular destinations for divers.

According to an UNESCO estimate, there are more than 3 million shipwrecks currently resting on the ocean floors, some are even recognised as underwater cultural heritage sites. While a significant chunk of these shipwrecks are not accessible to recreational scuba divers owing to the extreme depths they sit in or because of their heritage status, there are numerous wrecks available for scuba divers to explore, many of them having significant historical contexts.

In contrast, freshwater environments like lakes and rivers tend to have fewer wrecks and underwater structures due to their shallower depths. While there are occasional artificial reefs created in freshwater, such as sunken cars or boats or small fishing vessels, they are not as common as in saltwater environments.

Conclusion

So whether you prefer the tranquil beauty of your local lake or the vibrant colors and diversity of marine life in the ocean, both will surely offer unique experience and memories for you to cherish.

Freshwater diving may offer a different set of challenges and opportunities for exploration, such as diving in unique geological formations, while saltwater diving may provide clearer visibility and access to a wider variety of marine life.

I have had my fair share of diving adventures both in freshwater and saltwater environments ranging from the vibrant Great Barrier Reef to the grassy beds of Ewens Lake in Canada. Personally, I am more of a sea exploration enthusiast so naturally biased towards saltwater diving but I can, in no way deny the unique charm associated with freshwater diving. You definitely need to experience both environments in their entirety to make the ultimate choice of preference.