It is a teen movie, pretty sure within the rom-com genre, watched on Netflix quite a few years back. American movie.
There’s a party on a larger boat, somehow a boy and a girl, both tipsy, ends up in a plastic boat (?) and drifts off on the ocean. They drift in on the shore of what looks like a stranded island. They try to survive and with this explores more and more of the island. At one point the girl discoverers “society” again, but chooses not to tell the guy because she wants to continue being with him. She starts going to “society” regularly, buying stuff like fruits or different sea-creatures and in front of the guy pretending she’s finding it in the wild to show off and make him impressed.
I don’t remember either start or ending, but if it reminds you of a movie, please tell me the title.
I think “Blue Lagoon” might be it.