It is mentioned in the two movies (Dead Man's Chest and At World's End) that Davy Jones cannot come ashore. He does once and when he does, he brings along a bucket of seawater to bypass the restriction.
What isn't explained is WHY he cannot come ashore, what would happen to him?
In DMTNT we see what happens to undead when they set foot on dry land. They essentially turn to ash, and vanish. We can infer that something similar would happen to Davy Jones.
For historic reasons, I'm keeping my previous answer here.
We assume that either he just is unable to, as if some invisible barrier would prevent him, or that he would perish or suffer immensely if he did so.
The most information we have was about the deal made,
Because of that love, Jones agreed to set foot on dry land once every ten years.
I feel like I’m right so look, would a god walk on buckets if tripping or being pushed over would kill him or take away his powers? No. It’s logical it’s more of a inconvenience and he’d just essentially “respawn” on the ship as it would still need a captain, his heart is still alive somewhere, yada ya, I’d assume it destroys his body same as it did his crew but because his heart is somewhere else he’d just regenerate on his ship as he’s a still alive, horror movie dead slashed logic if you don’t make sure he’s dead there’s go gonna be a sequel or if the body disappears. Which it’s would as he would turn to ash and disintegrate. Let’s not forget this man casually teleports onto ships like we see that in movie yaknow. He would do the same to his ship even if he tripped and just reacted quick enough so I can’t imagine it’s based off his reaction speed like wether he’s dead forever or not that would be a pointless complication as he would always react in time less he dies in the most lame way possible. So yeah respawn theory, and if you’re thinking why does that not seem so bad, it’s isn’t, he just can’t go be a farmer like everyone else can, he can’t retire, same as will, he could logically pop up into speaking distance of land and stay on boat, or do the bucket thing, but that’s so inconvenient being a ferry till love eventually comes seems better (calypso and kierra knightly respectively, forgot the in character name lol but wills lady and Davy Jones Cthulhu lady god who started the curse. With the promise in 100 years they would have a day together, most likely the same will happen with will and his girl when she dies with one Day together.
It must be something that is related with Davy Jones being the captain of the Flying Dutchman. Being the captain of this ship granted him immense power and immunity. He can survive any physical blow and even drowning can not kill him. And many more...
But everything has a flip-side too. That is he will not be able to come ashore. The consequences are not explained in the movie. We just have to accept that with great power often comes great restrictions.
We can still make some assumptions about the untold consequences though. If he broke the rule and came ashore then he might
lose the physical immunity and other powers given to him.
lose the captaincy of the Dutchman.
be destroyed because of disobeying the rule.
