Walkie talkies work better on water because radio waves travel in straight lines and nothing is in the way.
The short answer to why do walkie talkies work better on water is line of sight. UHF and VHF radio waves are essentially straight-line travelers. On land, hills, trees, buildings, and even your own body block or soak up those waves. Water is flat, empty, and smooth, nothing to stop the signal.
Walkie talkie range on water gets a double bonus. First, no obstacles, so the direct path stays clear. Second, the water surface reflects the signal too, which can fill in weak spots. Fishermen on a calm lake routinely report ranges double what they get in the woods, and that’s not marketing, that’s just empty space.
Here’s the thing nobody mentions: you’re also standing at the perfect height. The higher both antennas sit above the surface, the further the horizon is. A couple of boats can sometimes talk right over the horizon entirely because the wave bends slightly with humidity near the surface. It’s a quirk of atmospheric conditions, not the radio doing anything special.
So if your plan is shoreline or lake use, buy accordingly, a waterproof handheld from the portable radios category is the move. And if you want to see the numbers behind it, our range test breaks down water versus forest versus city.