He spends most of the day on/in the sea.

[October wind]

Should I use “in” or “on”?

He is a fisherman. He spends most of the day on/in the sea.

Which is more natural? On or in?

 

[PeterCW]

On a boat you are "on" the sea. If you are swimming you are "in" the sea.

 

[teechar]

To me, neither "on" nor "in" works in that sentence.
I would say "He spends most of the day (out) at sea".

 

[October wind]

To me, neither "on" nor "in" works in that sentence.
I would say "He spends most of the day (out) at sea".

Thank you very much. What about the following?
1) fish on the sea
2) fish in the sea
3) fish at the sea

 

[emsr2d2]

Thank you very much. What about the following?
1) fish on the sea
2) fish in the sea
3) fish at the sea

Please give us complete sentences to look at.