Explore the lantern-lit streets, historic houses and the iconic Japanese Bridge; the ticket for several heritage sites is typically required (open daytime until evening).
Quick architectural stops in central Saigon — the cathedral square and post office are close together and ideal for morning photos (both generally open in the daytime).
Take a 1.5–2 hour river cruise or use the time for a final shopping run — both are good options when you have an evening flight (cruises often run 14:00–16:00).