Fishing with a magnet for my iPhone 6s+

[Speedy]

A fisherman with an underwater camera and depth finder.

[cbelt3]

A teenager with a diving mask will find it for $20. $10 if a teenaged girl is standing around in a bikini.

[sekker]

cbelt3 wrote:
A teenager with a diving mask will find it for $20. $10 if a teenaged girl is standing around in a bikini.

But she might charge $25...

[pqrst]

Most larger marinas i know have somebody who for a price will retrieve items dropped into the water. Ask the dockmaster, or boaters.