Stream2Sea
Quick verdict: “Reef-safe” is not a regulated term, which means most of the bottles carrying it have never been near a piece of coral. Stream2Sea is the exception. Autumn Blum is a cosmetic chemist and a diver, and she built the company after a trip to Palau made her look at what was washing off everyone’s skin. The products get tested on coral larvae and fish, and the results get published. It’s an ugly white cast and a small range. Our rating: 4.2 out of 5.
Who they are
Blum founded Stream2Sea in Florida in 2015. The company is woman-owned, veteran-operated, and independent, and it’s small enough that the founder’s chemistry background is the product strategy rather than a bio line.
The distinguishing decision was spending money on aquatic toxicity testing that no regulation required. Nothing forces a sunscreen brand to check whether its formula harms coral. Stream2Sea checked, and then published what came back.
What they get right
EWG Verified on ten products, which we confirmed in EWG’s verified directory rather than off the packaging.
It tested, and it says what the tests found. Stream2Sea commissioned toxicity work on coral larvae and juvenile fish, and reports zero mortality and no inhibition of coral larval settlement, against comparison products that did cause harm in the same tests. Our greenwashing guide tells readers to look for claims backed by something checkable. This is what that looks like when a brand actually does it.
Protect Land + Sea certification, an independent mark verifying the absence of a defined list of chemicals harmful to aquatic environments.
Non-nano zinc oxide as the active, which is the formulation that reef guidance and the Hawaii legislation actually point to.
Tree-free packaging made from post-consumer waste, and the brand is unusually candid that this is a small piece of a bigger problem.
Where they fall short
It leaves a cast. Meaningful non-nano zinc always does, and Stream2Sea’s tinted versions reduce it rather than remove it. On deeper skin tones the untinted formula is a real limitation, not a cosmetic gripe.
The texture is thick and takes work to spread. That’s the price of the zinc load, and it’s why people who don’t dive often drift to a lighter formula.
The range is narrow, and outside sunscreen and a few wash products there isn’t much. The certification stack is thinner than the leaders too: Protect Land + Sea is meaningful and specific, but there’s no B Corp or MADE SAFE covering the company or the wider formula.
What they sell and what it costs
Mineral sunscreens in several SPFs and tints, lip balm, body wash, shampoo and conditioner sized for travel and dive trips. Sunscreen typically runs $18 to $28, which sits above drugstore mineral and below the boutique reef brands.
Who it’s actually for
Divers, snorkelers, swimmers, and anyone who spends real time in water and would rather the claim on the bottle have been tested. It’s also the right pick if you’re travelling somewhere with a sunscreen ban and want to be certain you comply.
If you want a mineral sunscreen for school runs and a cosmetic finish matters more than reef testing, Badger or Attitude are easier to live with.
Deals and discounts
No affiliate program on our side, so nothing here earns us anything.
Related reading
- Reef-Safe Sunscreen: 7 Mineral Picks That Rub In
- 7 Skincare Ingredients to Avoid
- How to Spot Greenwashing: 4 Tactics Brands Still Use
Frequently asked questions
Is Stream2Sea actually reef-safe?
It’s the closest thing to a tested answer in this category. The brand commissioned aquatic toxicity work on coral larvae and juvenile fish and published the results, and it holds Protect Land + Sea certification. Worth repeating that “reef-safe” is not a regulated term, so on any other bottle it means whatever the marketing department decided it means.
Does Stream2Sea leave a white cast?
Yes. Non-nano zinc at a protective level sits on top of skin and reflects light, and that is visible. The tinted versions cut it down without eliminating it. If an invisible finish is non-negotiable, no mineral sunscreen will satisfy you, including this one.
Who owns Stream2Sea?
It’s independent, woman-owned and veteran-operated, founded in 2015 by cosmetic chemist Autumn Blum and still run by her. No parent company.
Is it worth paying more than drugstore mineral sunscreen?
If you’re in the water, yes, because the difference you’re paying for is the testing and the water resistance rather than the branding. If your sun exposure is walking to the car, a cheaper non-nano zinc from Badger or Attitude protects your skin just as well.