Stream2Sea Mask Defog Review

My default anti-fog solution for both freshwater and saltwater diving. I use it in quarries, Lake Michigan, and on ocean dives, and it has proven far more reliable than spit, baby shampoo, or random boat defogs. It continues working even if the mask floods or gets dunked during setup, and it is the only defog I trust around aquatic environments. It costs more than DIY options, but the reliability easily justifies the per-dive cost.

By Tyler Allison · Updated July 2025

Use: Quarry, Lake Michigan, and ocean dives
Current role: My default mask defog
Still in my kit: Yes

The Short Version

Stream2Sea has earned a permanent place in my kit because it works consistently in the conditions where cheaper defogs let me down. It holds up better after mask flooding or accidental dunking, but it still needs reapplication for each dive. The extra cost is small enough that I would rather pay it than keep dealing with unreliable fog prevention.

Would I buy it again? Yes. It is the defog I actively recommend and repurchase.

What Works

Consistent fog prevention when applied correctly
Better resistance to flooding and dunking than baby shampoo in my use
No dilution required
No irritation reported during repeated use
Secure travel cap and a nozzle that works reliably

What Doesn't

Costs more than DIY options
Harder to find in stores
Needs reapplication for each dive, not one application for an entire charter day

Why I Chose Stream2Sea

I tried spit, baby shampoo, and assorted boat defogs over the years, but I kept looking for something more predictable. Most of my Chicago-area diving is in freshwater quarries or Lake Michigan, and I wanted a defog that would not fail during cold or rushed kit-ups.

Stream2Sea worked well in those situations. I also shared it with students and buddies who had been using baby shampoo or boat defog, and they reported a noticeable improvement. Their feedback matched what I was seeing in my own mask.

What It Is Like to Use

Fog Prevention: I have not had a fog problem when applying a pea-sized amount correctly. No dilution is needed; my routine is to apply, rub, rinse, and use the mask.
Flooding and Dunking: It holds up better than baby shampoo when the mask gets dropped into the water during setup or floods during a dive. That resilience is one of its most useful differences for me.
Reapplication: I reapply it for each dive. It is not a product I expect to cover several consecutive dives from one application, so I allow time for another application between dives.
Comfort: I have not had irritation reported from the repeated use described in this review, including training days. That is my use experience, not a guarantee about how every diver will react.

Ownership, Cost, and Environmental Considerations

The nozzle works well and the travel cap stays secure. There is nothing especially elaborate about the bottle, but it does the practical job I need it to do.

It costs more than baby shampoo, but the per-dive cost in my original assessment was roughly a nickel. That is an ownership estimate, not a current price quote. For me, predictable performance makes the difference worthwhile.

Aquatic testing and ingredient transparency were also part of why I chose it. I wanted a product with documented testing for its intended use rather than rely on a household alternative. Those considerations support my preference; the review's firsthand evidence is how the defog has performed in my diving.

Who It Makes Sense For

It makes sense for divers who need dependable fog prevention during skills practice, teaching sessions, or cold-water kit-ups. It has worked well for me in freshwater and ocean diving, including situations where a mask gets flooded or dunked.

I would choose something else only if the lowest possible DIY cost were the overriding priority. I would not choose it expecting one application to last all day. My baby shampoo review explains why that cheaper option no longer fits my own diving.