Continuity mistake: When Dickie and Tom go out on the boat, Dickie is wearing his white jacket. When Tom swims back to shore, the white jacket is dry on the rocks as if Dickie hadn't taken it with him.
Continuity mistake: When Tom is with Peter on the boat sailing to Greece and Tom says he's going to watch the sunset, the sun is just above the horizon. When Tom goes into Peter's room after talking with Marge, you can see the sun in the exact same position out the porthole window in Peter's room.
Continuity mistake: When Tom is taking Freddy's body out of his building, Freddy's coat is buttoned to the top. When Tom puts Freddy in the car, his coat is suddenly undone and blood is visible on his shirt. (01:28:00)
Other mistake: Tom Ripley's ticket says first class in the limo, but when he boards, the rich girl says she saw his stuff in the third class stack. Dickie also says that he's a third class mooch, but according to his ticket he rode first class, so that'd make him a first class mooch, not third. His cabin is never shown. (00:07:20)
Chosen answer: Tom & his lover are travelling on a boat. The rich girl, who knows Tom as Dickie is also on the boat. If they were to meet, Tom's false identity would have been revealed, and the lover would have been able to figure out that Tom actually murdered Dickie.
marfbody