This movie only used the first half of the novel by José Giovanni. The second half of the book was adapted into the film Law of Survival (1967) (La loi du survivant) starring Michel Constantin, which was directed Giovanni himself.
The african filmmaker Sembene Osmane played a small part in Les aventuriers. He is the bus driver who runs after Serge Reggiani to be paid.
A (kind of) sequel was made in 1983: The Ruffian. It was directed by José Giovanni (who also wrote Les Aventuriers) and again starred Lino Ventura. Delon was replaced with the young actor Bernard Giraudeau. The plot again is about the hunt for some hidden underwater treasure but now set in Canada.
Lino Ventura and Alain Delon did not like so much to play with Joanna Shimkus, because they considered her not good enough. She was a beginner in the acting business.
After the first screen test projection with the distributors, after a big meal with booze, no one appreciated the film. But a few days later, in the late afternoon and with their families, every one in the audience loved the movie.