Do any aircraft carry boats? A small boat could be part of general cargo, but that would typically just mean it's unloaded at an airport and transported to the nearest body of water by land infrastructure. This is not what I'm looking for.

Instead, is there any aircraft that can directly deploy a boat to (or retrieve one from) water?

I would imagine there are cases when moving a boat by plane could be useful, especially when there's little or no infrastructure available on land.

Does such an aircraft exist?
Yes. During and after WW2 several aircraft were converted to serve as "Dumbo" aircraft, dropping boats or rafts near people in distress. Other models were used as well, but the B-17 were among the most prominent. Most were retired when the helicopter gradually took over rescue operations.