I've had these in my garden (not submerged in water) for 18 months now and still going strong. About to buy some more. Even in the depths of Winter we get light from them well past midnight (Perth).
I am excited as I got my solar lights for the pond!!! The light arrived well packed with bubble wrap to protect the box and its contents. Left the lights in the light for a day without turning them on. After a day bright lights :-) Brighter than I expected. Tested in pond, yes waterproof. All great!
underwater solar lightsolar pool lightsolar lights for pond