Leonardo DiCaprio's character in "Titanic" didn't have much to his name when he got on the ship ... and now Jack Dawson's outfit is expected to sell for way over six figures.

The costume Leo wore in James Cameron's classic is going up for auction next month, with the winning bid predicted to fall somewhere between $115,000 and $230,000.

Remember ... Jack spent most of the film dressed in corduroy pants, overalls, a button-down long-sleeve shirt and a vest.

The garments include custom labels reading "MR: LEONARDO DICAPRIO" and "DATE: AUGUST '96."

Leo's "Titanic" costume is part of Propstore's upcoming auction in London ... where $13.8 million in film and TV memorabilia is expected to be sold off.

Other items of note include a light-up C-3PO head from "Star Wars: A New Hope" ... which the auction house believes will go for $1.15 million.

Michael Keaton's batsuit from 1989's "Batman" is also on the auction block ... along with Jack Sparrow's stunt costume from "Pirates of the Caribbean: On Stranger Tides," Tom Hanks' sneakers from "Forrest Gump" and a Captain America shield from "Captain America: The First Avenger."